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Sample records for ag cu ti

  1. Ag- and Cu-doped multifunctional bioactive nanostructured TiCaPCON films

    Energy Technology Data Exchange (ETDEWEB)

    Shtansky, D.V., E-mail: shtansky@shs.misis.ru [National University of Science and Technology “MISIS”, Leninsky prospekt 4, Moscow 119049 (Russian Federation); Batenina, I.V.; Kiryukhantsev-Korneev, Ph.V.; Sheveyko, A.N.; Kuptsov, K.A. [National University of Science and Technology “MISIS”, Leninsky prospekt 4, Moscow 119049 (Russian Federation); Zhitnyak, I.Y.; Anisimova, N.Yu.; Gloushankova, N.A. [N.N. Blokhin Russian Cancer Research Center of RAMS, Kashirskoe shosse 24, Moscow 115478 (Russian Federation)

    2013-11-15

    A key property of multicomponent bioactive nanostructured Ti(C,N)-based films doped with Ca, P, and O (TiCaPCON) that can be improved further is their antibacterial effect that should be achieved without compromising the implant bioactivity and biocompatibility. The present work is focused on the study of structure, chemical, mechanical, tribological, and biological properties of Ag- and Cu-doped TiCaPCON films. The films with Ag (0.4–4 at.%) and Cu (13 at.%) contents were obtained by simultaneous sputtering of a TiC{sub 0.5}–Ca{sub 3}(PO{sub 4}){sub 2} target and either an Ag or a Cu target. The film structure was studied using X-ray diffraction, transmission and scanning electron microscopy, energy dispersive X-ray spectroscopy, glow discharge optical emission spectroscopy, and Raman-shift and IR spectroscopy. The films were characterized in terms of their hardness, elastic modulus, dynamic impact resistance, friction coefficient and wear rate (both in air and normal saline), surface wettability, electrochemical behavior and Ag or Cu ion release in normal saline. Particular attention was paid to the influence of inorganic bactericides (Ag and Cu ions) on the bactericidal activity against unicellular yeast fungus Saccharomyces cerevisiae and gram-positive bacteria Lactobacillus acidophilus, as well as on the attachment, spreading, actin cytoskeleton organization, focal adhesions, and early stages of osteoblastic cell differentiation. The obtained results show that the Ag-doped films are more suitable for the protection of metallic surfaces against bacterial infection compared with their Cu-doped counterpart. In particular, an excellent combination of mechanical, tribological, and biological properties makes Ag-doped TiCaPCON film with 1.2 at.% of Ag very attractive material for bioengineering and modification of load-bearing metal implant surfaces.

  2. Photocatalytic comparison of Cu- and Ag-doped TiO2/GF for bioaerosol disinfection under visible light

    Science.gov (United States)

    Pham, Thanh-Dong; Lee, Byeong-Kyu

    2015-12-01

    Photocatalysts, TiO2/glass fiber (TiO2/GF), Cu-doped TiO2/glass fiber (Cu-TiO2/GF) and Ag-doped TiO2/glass fiber (Ag-TiO2/GF), were synthesized by a sol-gel method. They were then used to disinfect Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in bioaerosols under visible light irradiation. TiO2/GF did not show any significant disinfection effect. Both Cu and Ag acted as intermediate agents to enhance separation efficiency of electron-hole pairs of TiO2, leading to improved photocatalytic activity of Cu-TiO2/GF and Ag-TiO2/GF under visible light. Cu in Cu-TiO2/GF acted as a defective agent, increasing the internal quantum efficiency of TiO2, while Ag in Ag-TiO2/GF acted as a sensitive agent, enhancing the transfer efficiency of the electrons generated. The highest disinfection efficiencies of E. coli and S. aureus by Cu-TiO2/GF were 84.85% and 65.21%, respectively. The highest disinfection efficiencies of E. coli and S. aureus by Ag-TiO2/GF were 94.46% and 73.12%, respectively. Among three humidity conditions - 40±5% (dry), 60±5% (moderate), and 80±5% (humid) - the moderate humidity condition showed the highest disinfection efficiency for both E. coli and S. aureus. This study also showed that a Gram-negative bacterium (E. coli) were more readily disinfected by the photocatalysts than a Gram-positive bacterium (S. aureus).

  3. Active Brazing of C/C Composite to Copper by AgCuTi Filler Metal

    Science.gov (United States)

    Zhang, Kexiang; Xia, Lihong; Zhang, Fuqin; He, Lianlong

    2016-05-01

    Brazing between the carbon-fiber-reinforced carbon composite (C/C composite) and copper has gained increasing interest because of its important application in thermal management systems in nuclear fusion reactors and in the aerospace industry. In order to examine the "interfacial shape effect" on the mechanical properties of the joint, straight and conical interfacial configurations were designed and machined on the surface of C/C composites before joining to copper using an Ag-68.8Cu-4.5Ti (wt pct) alloy. The microstructure and interfacial microchemistry of C/C composite/AgCuTi/Cu brazed joints were comprehensively investigated by using high-resolution transmission electron microscopy. The results indicate that the joint region of both straight and conical joints can be described as a bilayer. Reaction products of Cu3Ti3O and γ-TiO were formed near the copper side in a conical interface joint, while no reaction products were found in the straight case. The effect of Ag on the interfacial reaction was discussed, and the formation mechanism of the joints during brazing was proposed. On the basis of the detailed microstructure presented, the mechanical performance of the brazed joints was discussed in terms of reaction and morphology across the joint.

  4. Electrical Properties of Al, Ag, Cu, Ti and SS Thin Film for Electrode of Solar Cell

    International Nuclear Information System (INIS)

    The Al, Ag, Cu, Ti and SS materials were deposited on the surface of glass substrate using plasma DC sputtering technique. The deposition process was done with the following plasma parameters : deposition time, gas pressure and substrate temperature with the aim to obtain a good conductance of thin films. Variation of substrate deposition time was 1 - 15 minutes, gas pressure was 5x10-2 - 7x10-2 torr and of temperature was 100 - 300 oC. The resistance measurement has been done by four points probes and the conductivity was calculated using mathematic formulation. It was obtained that the minimum resistance in the order of R = 0.07 Ω, was found at Ag materials and this was obtained at the following plasma parameters : deposition time 15 minutes, gas pressure 6x10-2 torr and temperature 300 oC, while, the resistance of : Cu, Al, Ti and SS materials were R = 0.13 Ω, R = 450 Ω, R = 633 Ω, R = 911 Ω respectively, It could be concluded that the Ag thin film has a minimum resistance, high conductivity compared to the other materials Al, Cu, Ti and SS. Ag is therefore the suitable material for applying as electrode of solar cell. (author)

  5. Brazing of SiC Ceramics Using Ag-Cu-In-Ti Filler Metal

    OpenAIRE

    LIU Yan,HUANG Zheng-Ren,LIU Xue-Jian,YUAN Ming

    2009-01-01

    Sintered silicon carbide was jointed with itself using Ag-Cu-In-Ti filler metal successfully. Interfacial microstructure was investigated by electron probe microanalysis (EPMA) and transmission electron microscope (TEM). Joining strength of SiC/SiC joints was measured by four-point flexural strength. The experimental results indicate that joining strength has a peak value with the joining temperature increasing, and the max flexural strength reaches 234MPa, however joining strength decreases ...

  6. Metal-gas reactions in arc plasma spraying of Ag, Cu, Ni, Ti, TiC, W, Zn, and Zr

    International Nuclear Information System (INIS)

    Powders of Ag, Cu, Ni, Ti, TiC, W, Zn, and Zr were arc sprayed with the plasma gas mixtures Ar + 30% He, Ar + 10% N2, and Ar + 10% vol.% H2 in a closed chamber containing the same atmosphere and in air and the extents of gas-metal reaction were determined by X-ray analyses. Spraying in the Ar-N2 and Ar-H2 mixtures led to some N2 and H2 uptake by Ti and Zr coatings and to some reduction of oxygen impurity in the Cu, W, Zn, and probably, Ni coatings. Coatings sprayed in air contained appreciable amounts of the respective impurity phases Cu2O, NiO, TiN, TiO2, Ti(C,N), β-W, possibly ZnO, ZrN, and ZrO2. Samples of sprayed products collected at different distances show that metal-gas reactions occurring with the powder particles in flight is often a minor source of contamination compared to that stemming from gas uptake by the coating after the metal is deposited. Deviations from the Engelke difficulty of melting parameter occurs when a sufficiently intense chemical reaction takes place between the metal particles and the plasma gases. (orig.)

  7. The evolution of interface microstructure in a ZrO2/Ag-Cu-Al-Ti system

    International Nuclear Information System (INIS)

    Among ceramic/metal (C/M) joining technologies, the active filler metal method has been studied extensively due to the simple brazing process and excellent joint strength. Active metal elements, typically Ti, are intentionally added to braze alloys to enhance the formation of reaction products between the ceramic and the braze metal at the C/M interface. In the brazing of Al2O3 with the Ag-Cu-Ti filler metal, reaction products such as γ-TiO, Cu2(Ti, Al)4O, Ti3(Cu0.76Al0.18Sn0.06)3O were found, while products such as Ti5Si3 and TiN formed in the brazing of Si3N4. The presence of reaction layers at the C/M interface influences the interface strength in a complex way. In Cu/Al2O3, Co/Al2O3, Ni/Al2O3, and Cu/diamond systems, maxima of joint strength were observed at some intermediate Ti addition, while the flexural strength decreased substantially with the thickening of the TiO layer in a ZrO2/Ag-Cu-Sn-Ti system. Thus, composition of the braze alloy (particularly, the content of the active metal), process conditions such as brazing temperature and time, microstructure and mechanical properties of reaction products at the C/M interfaces, interfacial chemistry, and residual stress are primary factors to be studied in order to understand the strengths of the C/M interfaces systematically. In the present and the following papers, evolutions of interfacial microstructures at various brazing conditions, and corresponding interface strengths are reported, respectively, for a ZrO2/Ag-Cu-Al-Ti system

  8. Microstructure evolution and mechanical properties of vacuum-brazed C/C composite with AgCuTi foil

    International Nuclear Information System (INIS)

    The microstructure and bonding strength of vacuum-brazed C/C composite and C/C composite with AgCuTi foil are studied. The interface structure of the brazed joint is C/C composite–TiC–eutectic structure of AgCu–TiC–C/C composite. The maximum shear strength of the joint is about 20 MPa and TiC formed at the edge of C/C composite plays a key role in the brazing process. It improves the wettability of the C/C composite and inhibits diffusion of the Ag and Cu atoms in the filler metal and C atoms in the C/C composite. The fracture mode of the brazing joint is brittle. The interface evolution in the brazing process and associated mechanism are discussed

  9. Joining of CBN abrasive grains to medium carbon steel with Ag-Cu/Ti powder mixture as active brazing alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ding, W.F. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)]. E-mail: dingwf2000@vip.163.com; Xu, J.H. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Shen, M. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Su, H.H. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Fu, Y.C. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Xiao, B. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

    2006-08-25

    In order to develop new generation brazed CBN grinding wheels, the joining experiments of CBN abrasive grains and medium carbon steel using the powder mixture of Ag-Cu alloy and pure Ti as active brazing alloy are carried out at elevated temperature under high vacuum condition. The relevant characteristics of the special powder mixture, the microstructure of the interfacial region, which are both the key factors for determining the joining behavior among the CBN grains, the filler layer and the steel substrate, are investigated extensively by means of differential thermal analysis (DTA), scanning electron microscope (SEM) and energy dispersion spectrometer (EDS), as well X-ray diffraction (XRD) analysis. The results show that, similar to Ag-Cu-Ti filler alloy, Ag-Cu/Ti powder mixture exhibits good soakage capability to CBN grains during brazing. Moreover, Ti in the powder mixture concentrates preferentially on the surface of the grains to form a layer of needlelike Ti-N and Ti-B compounds by chemical metallurgic interaction between Ti, N and B at high temperature. Additionally, based on the experimental results, the brazing and joining mechanism is deeply discussed in a view of thermodynamic criterion and phase diagram of Ti-B-N ternary system.

  10. Synthesis of TiCuAg thick film inks for glass frit free metallization of aluminium nitride

    International Nuclear Information System (INIS)

    A glas frit free screen printing ink for metallization of AIN was developed. Bonding to the substrate is achieved by active metal additives. The metallic component consists of Cu and Ag powder synthesized from inorganic salts by the polyol process, and Cu-Ti powder synthesized by arc melting, milling and ultracentrifugation. This ternary powder mixture was introduced to a specifically developed organic vehicle and screen printed onto AIN. The detailed development process and the results will be presented. (author)

  11. Study on the Characteristics of Ag Doped CuO-BaTiO3 CO2 Sensors

    Directory of Open Access Journals (Sweden)

    Jinhuai Liu

    2002-09-01

    Full Text Available In this paper the characteristics of a CuO-BaTiO3 based CO2 gas sensor was investigated. The sensitivity of the CuO-BaTiO3 based CO2 sensor was influenced by doping various metal elements such as Au, Ag, Pt, Pd, Ce, Mg, Sr, La, Zn, Fe and Bi, which were added as a pure metal or in the form of metal oxides. It was found that Ag is the most suitable additive among all substances tested. The Ag-doped CO2 gas sensor has better sensitivity and lower operating temperature, with a detection concentration range of from 100 ppm to 10%. The sensor also shows good stability.

  12. A bamboo-inspired hierarchical nanoarchitecture of Ag/CuO/TiO2 nanotube array for highly photocatalytic degradation of 2,4-dinitrophenol.

    Science.gov (United States)

    Zhang, Xuhong; Wang, Longlu; Liu, Chengbin; Ding, Yangbin; Zhang, Shuqu; Zeng, Yunxiong; Liu, Yutang; Luo, Shenglian

    2016-08-01

    The optimized geometrical configuration of muitiple active materials into hierarchical nanoarchitecture is essential for the creation of photocatalytic degradation system that can mimic natural photosynthesis. A bamboo-like architecture, CuO nanosheets and Ag nanoparticles co-decorated TiO2 nanotube arrays (Ag/CuO/TiO2), was fabricated by using simple solution-immersion and electrodeposition process. Under simulated solar light irradiation, the 2,4-dinitrophenol (2,4-DNP) photocatalytic degradation rate over Ag/CuO/TiO2 was about 2.0, 1.5 and 1.2 times that over TiO2 nanotubes, CuO/TiO2 and Ag/TiO2, respectively. The enhanced photocatalytic activity of ternary Ag/CuO/TiO2 photocatalyst was ascribed to improved light absorption, reduced carrier recombination and more exposed active sites. Moreover, the excellent stability and reliability of the Ag/CuO/TiO2 photocatalyst demonstrated a promising application for organic pollutant removal from water. PMID:27107324

  13. Surface-enhanced Raman scattering (SERS) activity of Ag, Au and Cu nanoclusters on TiO2-nanotubes/Ti substrate

    International Nuclear Information System (INIS)

    Tubular arrays of TiO2 nanotubes (ranging in diameter from 40 to 110 nm) on a Ti substrate were used as a support for Ag, Au or Cu deposits obtained by the sputter deposition technique, where the amount of metal varied from 0.01 to 0.2 mg/cm2. Those composite supports were intended for surface-enhanced Raman scattering (SERS) investigations. Composite samples were studied with the aid of scanning electron microscopy (SEM) and Auger electron spectroscopy (AES) to reveal their characteristic morphological and chemical features. Raman spectra of pyridine (as a probe molecule) were measured at different cathodic potentials ranging from -0.2 down to -1.2 V after the pyridine had been adsorbed on the metal-covered TiO2 nanotube/Ti substrates. In addition, SERS spectra on a bulk standard activated Ag, Au and Cu substrates were also measured. The SERS activity of the composite samples was strongly dependent on the amount of metal deposit, e.g. at and above 0.06 mg Ag/cm2, the intensity of SERS signal was even higher than that for the Ag reference substrate. The high activity of these composites is mainly a result of their specific morphology. The high SERS sensitivity on the surface morphology of the substrate made it possible to monitor very small temporal changes in the Ag metal clusters. This rearrangement was not detectable with microscopic (SEM) or microanalytical (AES) methods. The SERS activity of Au or Cu clusters was distinctly lower than those of Ag. The spectral differences exhibited by the three kinds of composites as compared to the reference metal samples are discussed.

  14. Effects of processing parameters on microstructure and mechanical behavior of SiO2/Ti-6Al-4V joint brazed with AgCu/Ni interlayer

    International Nuclear Information System (INIS)

    SiO2 glass ceramic has been successfully joined to Ti-6Al-4V alloy with AgCu/Ni composite interlayer. The brazing temperature varies from 950 deg. C to 980 deg. C, with the holding time ranging from 1 min to 45 min. AgCu eutectic foil melted first, followed by the Ti-Cu-Ni ternary eutectic reaction, then Ti reacted to SiO2 glass ceramic. All of Ti atoms came from Ti-6Al-4V alloy but not from braze alloy. The effects of brazing temperature and dwelling time on interface structure and joint strength were investigated in the present work. The largest shear strength of brazed joint could reach 110 MPa when the brazing temperature was 970 deg. C, holding time was 10 min, and fracture occurred in the SiO2 glass ceramic part. While the thin reaction layer at SiO2 side is the weak part of the joint when the brazing parameter is not appropriate.

  15. Hydrogen Dissociation and Diffusion on Transition Metal(=Ti,Zr,V,Fe,Ru,Co,Rh,Ni,Pd,Cu,Ag)-doped Mg(0001) Surfaces

    OpenAIRE

    Pozzo, Monica; Alfe`, Dario

    2008-01-01

    The kinetics of hydrogen absorption by magnesium bulk is affected by two main activated processes: the dissociation of the H$_2$ molecule and the diffusion of atomic H into the bulk. In order to have fast absorption kinetics both activated processed need to have a low barrier. Here we report a systematic ab-initio density functional theory investigation of H$_2$ dissociation and subsequent atomic H diffusion on TM(=Ti,V,Zr,Fe,Ru,Co,Rh,Ni,Pd,Cu,Ag)-doped Mg(0001) surfaces. The calculations sho...

  16. Saltwater ecotoxicology of Ag, Au, CuO, TiO2, ZnO and C60 engineered nanoparticles: An overview.

    Science.gov (United States)

    Minetto, D; Volpi Ghirardini, A; Libralato, G

    2016-01-01

    This review paper examined 529 papers reporting experimental nanoecotoxicological original data. Only 126 papers referred to saltwater environments (water column and sediment) including a huge variety of species (n=51), their relative endpoints and engineered nanoparticles (ENPs) (n=38). We tried to provide a synthetic overview of the ecotoxicological effects of ENPs from existing data, refining papers on the basis of cross-cutting selection criteria and supporting a "mind the gap" approach stressing on missing data for hazard and risk assessment. After a codified selection procedure, attention was paid to Ag, Au, CuO, TiO2, ZnO and C60 ENPs, evidencing and comparing the observed nanoecotoxicity range of effect. Several criticisms were evidenced: i) some model organisms are overexploited like microalgae and molluscs compared to annelids, echinoderms and fish; ii) underexploited model organisms: mainly bacteria and fish; iii) exposure scenario variability: high species-specific and ENP scenarios including organism life stage and way of administration/spiking of toxicants; iv) scarce comparability between results due to exposure scenario variability; v) micro- and mesocosms substantially unexplored; vi) mixture effects: few examples are available only for ENPs and traditional pollutants; mixtures of ENPs have not been investigated yet; vii) effects of ions and ENPs: nAg, nCuO and nZnO toxicity aetiology is still a matter of discussion; viii) size and morphology effects of ENPs: scarcely investigated, justified and understood. Toxicity results evidenced that: nAu>nZnO>nAg>nCuO>nTiO2>C60. PMID:27107224

  17. Crystallization behavior and consolidation of ball milled Zr60Ti5Ag5Cu12.5Ni10Al7.5 glassy powders

    International Nuclear Information System (INIS)

    Devitrification and consolidation of Zr60Ti5Ag5Cu12.5Ni10Al7.5 glassy powders produced by ball milling of intermetallic compounds have been investigated. The crystallization behavior is characterized by the formation of a nanoscale quasicrystalline phase along with a minor amount of tetragonal Zr2Cu phase during the first stage of the crystallization process. In the second crystallization event the metastable QC transform into the tetragonal Zr2Cu phase. The viscous flow of the supercooled liquid was studied by parallel plate rheometry, showing a distinct viscosity drop related to the glass transition, corroborating the results from DSC measurements. Consolidation of the glassy powders was performed by uniaxial hot pressing. The consolidation parameters were properly selected in order to obtain partially crystallized bulk samples with a composite microstructure characterized by the contemporary presence of glassy, quasicrystalline and tetragonal Zr2Cu phases. Hardness measurements reveal a Vickers hardness of 4.61 GPa and an estimated yield strength of 1.53 GPa. These results show that powder metallurgy methods are suitable for the production of Zr-based alloys characterized by a composite microstructure consisting of glassy, quasicrystalline and crystalline phases with mechanical properties similar to materials prepared by other techniques

  18. Estimation of Ba, Ag, Sn, Ti, Cu, Zn, Y and Zr in carbonaceous rocks using energy dispersive X-ray fluorescence spectrometer

    International Nuclear Information System (INIS)

    Carbonaceous rocks include carbon phyllites, carbonaceous shale, coal, variants of coaly sandstone, carbonaceous sandstone and graphite schist. Estimation of trace elements in these rocks by X-ray Fluorescence (XRF) method is generally done using coal ash samples. However, one advantage of analyzing whole coal is that volatile elements which are normally lost in ashing, can also be determined. XRF analysis is a rapid, nondestructive comparative method for which a number of matching geostandards/certified reference materials (CRM) is required. Estimation of Ag, Sn, Cu, Ba, Ti, Y and Zr in bromo heavies separated from whole coal samples has been attempted using EDXRFS by formulating procedures with pressed pellets of CRMs comprising of soil (SO-1, SO-2, SO-3, SO-4), shale (SCO-1, SGR-1, SDC-1, GXR-2, GXR-4, GXR-6) and schist rock (ASK-2)

  19. Temperature stability of AgCu nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Sopoušek, Jiří, E-mail: sopousek@mail.muni.cz; Zobač, Ondřej; Vykoukal, Vít [Masaryk University, Department of Chemistry, Faculty of Science (Czech Republic); Buršík, Jiří; Roupcová, Pavla [Institute of Physics of Materials ASCR (Czech Republic); Brož, Pavel; Pinkas, Jiří [Masaryk University, Department of Chemistry, Faculty of Science (Czech Republic); Vřešťál, Jan [Masaryk University, Central European Institute of Technology, CEITEC (Czech Republic)

    2015-12-15

    The colloidal solutions of the Ag–Cu nanoparticles (NPs, 10–32 nm) were prepared by solvothermal reactions. The samples of dried AgCu NPs and the resulting microstructures after heat treatment in air were investigated by various methods including electron microscopy (TEM, SEM) and high-temperature X-ray powder diffraction (HTXRD). The AgCu randomly mixed, Cu-rich, and Ag-rich face centred cubic crystal lattices were detected during the experiments. The temperature induced sintering was observed experimentally by HTXRD at 250 °C. The phase transformations at high temperatures were monitored by differential scanning calorimetry. The formation of the Ag-rich grains during heating in air and evolution of copper oxide microstructure were detected.Graphical abstract.

  20. Advances of Ag, Cu, and Ag-Cu alloy nanoparticles synthesized via chemical reduction route

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Kim Seah; Cheong, Kuan Yew, E-mail: cheong@eng.usm.my [Universiti Sains Malaysia, Electronic Materials Research Group, School of Materials and Mineral Resources Engineering (Malaysia)

    2013-04-15

    Silver (Ag) and copper (Cu) nanoparticles have shown great potential in variety applications due to their excellent electrical and thermal properties resulting high demand in the market. Decreasing in size to nanometer scale has shown distinct improvement in these inherent properties due to larger surface-to-volume ratio. Ag and Cu nanoparticles are also shown higher surface reactivity, and therefore being used to improve interfacial and catalytic process. Their melting points have also dramatically decreased compared with bulk and thus can be processed at relatively low temperature. Besides, regularly alloying Ag into Cu to create Ag-Cu alloy nanoparticles could be used to improve fast oxidizing property of Cu nanoparticles. There are varieties methods have been reported on the synthesis of Ag, Cu, and Ag-Cu alloy nanoparticles. This review aims to cover chemical reduction means for synthesis of those nanoparticles. Advances of this technique utilizing different reagents namely metal salt precursors, reducing agents, and stabilizers, as well as their effects on respective nanoparticles have been systematically reviewed. Other parameters such as pH and temperature that have been considered as an important factor influencing the quality of those nanoparticles have also been reviewed thoroughly.

  1. Screening on binary Zr-1X (X = Ti, Nb, Mo, Cu, Au, Pd, Ag, Ru, Hf and Bi) alloys with good in vitro cytocompatibility and magnetic resonance imaging compatibility.

    Science.gov (United States)

    Zhou, F Y; Qiu, K J; Li, H F; Huang, T; Wang, B L; Li, L; Zheng, Y F

    2013-12-01

    In this study, the microstructures, mechanical properties, corrosion behaviors, in vitro cytocompatibility and magnetic susceptibility of Zr-1X alloys with various alloying elements, including Ti, Nb, Mo, Cu, Au, Pd, Ag, Ru, Hf and Bi, were systematically investigated to explore their potential use in biomedical applications. The experimental results indicated that annealed Zr-1X alloys consisted entirely or primarily of α phase. The alloying elements significantly increased the strength and hardness of pure Zr and had a relatively slight influence on elastic modulus. Ru was the most effective enhancing element and Zr-1Ru alloy had the largest elongation. The results of electrochemical corrosion indicated that adding various elements to Zr improved its corrosion resistance, as indicated by the reduced corrosion current density. The extracts of the studied Zr-1X alloys produced no significant deleterious effects on osteoblast-like cells (MG 63), indicating good in vitro cytocompatibility. All except for Zr-1Ag alloy showed decreased magnetic susceptibility compared to pure Zr, and Zr-1Ru alloy had the lowest magnetic susceptibility value, being comparable to that of α' phase Zr-Mo alloy and Zr-Nb alloy and far lower than that of Co-Cr alloy and Ti-6Al-4V alloy. Among the experimental Zr-1X alloys, Zr-1Ru alloy possessing high strength coupled with good ductility, good in vitro cytocompatibility and low magnetic susceptibility may be a good candidate alloy for medical devices within a magnetic resonance imaging environment. PMID:23928334

  2. Mechanical properties of cold-rolled Zr{sub 60}Ti{sub 5}Ag{sub 5}Cu{sub 12.5}Ni{sub 10}Al{sub 7.5} metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Scudino, Sergio; Surreddi, Kumar Babu [IFW Dresden, Institut fuer Komplexe Materialien, Postfach 270116, 01171 Dresden (Germany); Eckert, Juergen [IFW Dresden, Institut fuer Komplexe Materialien, Postfach 270116, 01171 Dresden (Germany); TU Dresden, Institut fuer Werkstoffwissenschaft, 01062 Dresden (Germany)

    2010-05-15

    In this work, the effect of cold-rolling on the mechanical behavior of the Zr{sub 60}Ti{sub 5}Ag{sub 5}Cu{sub 12.5}Ni{sub 10}Al{sub 7.5} metallic glass has been investigated. The results reveal that cold-rolling is very effective for improving the room temperature mechanical properties of the material. A small size reduction of only 5% remarkably improves the strength as well as the plastic deformation, which increase by about 20 and 40%, respectively, with respect to the as-cast material. The origin of the enhanced mechanical properties is most likely due to the creation during cold-rolling of a heterogenous microstructure consisting of shear softened regions surrounded by hard undeformed regions. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  3. Effect of Cooling Rate on the Microstructure and Mechanical Properties of Sn-1.0Ag-0.5Cu-0.2BaTiO3 Composite Solder

    Science.gov (United States)

    Yang, Li; Ge, Jinguo; Liu, Haixiang; Xu, Liufeng; Bo, Anbing

    2015-11-01

    The microstructure, interfacial intermetallic compound (IMC) layer, microhardness, tensile properties, and fracture surfaces of Sn-1.0Ag-0.5Cu-0.2BaTiO3 composite solder were explored under three different cooling conditions (water-, air-, and furnace-cooled) during solidification. The average grain size was refined and the volume fraction of primary β-Sn dendrites increased with increasing cooling rate. The thickness of the IMC layer increased as the cooling rate was decreased, and the morphology also transformed from scallop shaped, for a rapid cooling rate, to irregular shaped for slower cooling; a Cu3Sn IMC layer was detected between the Cu6Sn5 IMC and copper substrate under the furnace-cooled condition, but not in water- or air-cooled specimens. The mechanical properties, including the microhardness and tensile properties, improved with rapid solidification due to the combined effects of grain refinement and a secondary strengthening mechanism. Fracture surfaces after tensile tests showed that the amount of dimples decreased and a cleavage-like pattern increased as the cooling rate was decreased from the water-cooled to furnace-cooled condition, so the fracture process transformed from ductile to mixed-mode fracture. A refined microstructure and excellent mechanical properties were obtained for the rapidly cooled sample.

  4. Modification of field emission resonances by Cu and Cu/Ag islands on Ag(100)

    Energy Technology Data Exchange (ETDEWEB)

    Zaum, Christopher; Morgenstern, Karina [Institut fuer Festkoerperphysik, Abteilung ATMOS, Gottfried Wilhelm Leibniz Universitaet, Appelstr. 2, D-30167 Hannover (Germany)

    2011-07-01

    We deposited Cu islands containing 10 to 500 atoms on a clean Ag(100) surface at room temperature and investigated their electronic structure by STS spectroscopy with a low temperature scanning tunneling microscope. Islands containing less than 50 atoms per islands are pure Cu islands, while islands at sizes above 80 atoms per island are Cu/Ag alloy islands. STS measurements reveal that these two island types have a different impact on the field emission resonances (FERs) of the Ag(100) surface. While the observed modifications for large islands are marginal, noticeable shifts of the FERs occur for small islands. These different results in STS spectroscopy are discussed with respect to the different work functions of pure and alloyed islands. Such STS measurements could therefore be used to determine the composition of surface alloys with high spatial resolution.

  5. Phase-dependent corrosion of titanium-to-stainless steel joints brazed by Ag–Cu eutectic alloy filler and Ag interlayer

    International Nuclear Information System (INIS)

    The electrochemical corrosion properties of Ti–STS dissimilar joints brazed by a 72Ag–28Cu alloy filler and an Ag interlayer were studied in a 3.5% NaCl solution using potentiodynamic polarization and ac impedance spectroscopy. For a joint with a layered structure of Ti(base)/TiAg/Ag solid solution/Ag–Cu eutectic/STS(base), galvanic corrosion mostly occurred in the TiAg phase with a severe material loss, indicating that the TiAg layer acted as an anode in the galvanic couple in the layered joint. The Ag-rich solid solution layer was also corroded to a certain extent, but the corrosion in this layer was dominated by the selective pitting corrosion of the eutectic Cu-rich phase. With an increase in the brazing temperature, the Cu-rich phases disappeared owing to the enhanced isothermal solidification effect, leading to an improvement of the corrosion resistance

  6. Phase-dependent corrosion of titanium-to-stainless steel joints brazed by Ag–Cu eutectic alloy filler and Ag interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, M.K.; Park, J.J.; Lee, J.G., E-mail: jglee88@kaeri.re.kr; Rhee, C.K.

    2013-08-15

    The electrochemical corrosion properties of Ti–STS dissimilar joints brazed by a 72Ag–28Cu alloy filler and an Ag interlayer were studied in a 3.5% NaCl solution using potentiodynamic polarization and ac impedance spectroscopy. For a joint with a layered structure of Ti(base)/TiAg/Ag solid solution/Ag–Cu eutectic/STS(base), galvanic corrosion mostly occurred in the TiAg phase with a severe material loss, indicating that the TiAg layer acted as an anode in the galvanic couple in the layered joint. The Ag-rich solid solution layer was also corroded to a certain extent, but the corrosion in this layer was dominated by the selective pitting corrosion of the eutectic Cu-rich phase. With an increase in the brazing temperature, the Cu-rich phases disappeared owing to the enhanced isothermal solidification effect, leading to an improvement of the corrosion resistance.

  7. Bonding of Cf/SiC composite to Invar alloy using an active cement, Ag-Cu eutectic and Cu interlayer

    Science.gov (United States)

    Lei, Zhao; Xiaohong, Li; Jinbao, Hou; Qiang, Sun; Fuli, Zhang

    2012-10-01

    The interfacial microstructures and mechanical properties of the joints formed by active cement added brazing in vacuum of Cf/SiC composite to Invar alloy, using Ag-Cu eutectic alloy and pure copper foil as braze alloy and interlayer respectively, were investigated. CuTi, Cu4Ti3, Fe2Ti and the reaction layer of TiC and Si were the predominant components at the joint interface. The maximum shear strength of the joint was 77 MPa for brazing at 850 °C for 15 min. The results show that active cement added brazing in vacuum using Ag-Cu eutectic alloy and Cu interlayer can be used successfully for joining Cf/SiC composites to Invar alloy.

  8. Thermal stability of Cu@Ag core–shell nanoparticles

    International Nuclear Information System (INIS)

    Highlights: •Thermal stability of Cu@Ag core–shell NPs upon heating was evaluated. •Oxidation of nanoparticles was monitored by synchrotron radiation X-ray diffraction. •Phase transitions and morphological evolution were investigated. •Mechanisms for the coalescence of Cu cores and ripening of Ag shell were explained. -- Abstract: In this study, the structural evolution and oxidation of Cu@Ag core–shell nanoparticle deposits (with average particle diameter of 25 nm and Ag/Cu atomic ratio of 1/8) upon heating in air were investigated quantitatively via in situ synchrotron radiation X-ray diffraction. With an increasing temperature, the coalescence of Cu cores and ripening of Ag shell occurred simultaneously, resulting in discrete Ag nanonodules and unprotected Cu microparticles. Due to the protection of the thin Ag shell, the formation temperatures of the Cu oxides for Cu@Ag NPs were higher than those for pure Cu nanoparticles with similar size by at least 150 °C

  9. Evolution process of the synthesis of TiC in the Cu-Ti-C system

    International Nuclear Information System (INIS)

    The evolution process of TiC formation in the 20 wt.% Cu-Ti-C powder mixtures was studied by using differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The TixCuy compounds (Ti2Cu, TiCu, Ti3Cu4 and TiCu4) formed initially via solid-state diffusion reactions between Cu and Ti particles; and then Ti2Cu and TiCu can form a Cu-Ti eutectic liquids at about 1233 K. The unreacted Ti and C particles dissolved into the Cu-Ti liquids and led to the formation of Cu-Ti-C ternary liquids; subsequently, TiC particulates precipitated out of the saturated liquids. At the same time, also the formation of Ti2Cu occurred at the interface between the Cu-Ti liquids and the unreacted Ti particles. As the temperature increased further, the Ti2Cu melted and more Cu-Ti liquids formed; and then C particles continuously dissolved into the Cu-Ti-C liquids and TiC particulates gradually precipitated out of the saturated liquids

  10. Mechanical properties and microstructures of dental cast Ti-6Nb-4Cu, Ti-18Nb-2Cu, and Ti-24Nb-1Cu alloys.

    Science.gov (United States)

    Takahashi, Masatoshi; Kikuchi, Masafumi; Takada, Yukyo

    2016-01-01

    The mechanical properties -tensile strength, yield strength, elongation after fracture, and Vickers hardness- and alloy phases of the dental cast alloys Ti-6%Nb-4%Cu, Ti-18%Nb-2%Cu, and Ti-24%Nb-1%Cu were investigated. Ti-6%Nb-4%Cu consisted of a single α-phase, while Ti-18%Nb-2%Cu and Ti-24%Nb-1%Cu consisted of α- and β-phases. The tensile strengths, yield strengths, and hardnesses of these alloys were higher than those of Ti-5%Cu and Ti-30%Nb; however, their breaking elongations were smaller. These differences in the mechanical properties are attributable to solid-solution strengthening or to precipitation strengthening by the dual-phase (α+β) structure. Thus, Ti-Nb-Cu alloys are suitable for use in high-strength dental prostheses, such as implantretained superstructures and narrow-diameter implants. PMID:27477221

  11. Evidence for improvement of critical current by Ag in YBaCuO-Ag thick films

    Energy Technology Data Exchange (ETDEWEB)

    Dwir, B.; Kellett, B.; Mieville, L.; Pavuna, D. (Institute of Micro- and Opto-electronics, Department of Physics, Swiss Federal Institute of Technology, CH-1015 Lausanne, Switzerland (CH))

    1991-04-15

    The evidence is reported for enhancement of critical current density {ital J}{sub {ital c}} in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thick films with the addition of Ag, which is correlated with improvements in structural properties. An improvement of 50% in {ital J}{sub {ital c}} (up to {similar to}500 A/cm{sup 2} at {ital T}=4.2 K) was obtained in films made from YBCO+60wt % Ag powder, fabricated by the spin-on technique on (100) SrTiO{sub 3}, which is correlated with improvements in structure. The resulting films are 10 {mu}m thick, uniform, partially textured, and show good adherence. The critical temperature {ital T}{sub {ital c}} is improved by the addition of Ag, and a reduction in the density of microcracks and in the amount of secondary phases in the sintered films was observed. Normal-state resistivity is reduced by almost three orders of magnitude, making these films potentially useful for electronic applications in interconnects and novel hybrid circuits.

  12. Evidence for improvement of critical current by Ag in YBaCuO-Ag thick films

    Science.gov (United States)

    Dwir, B.; Kellett, B.; Mieville, L.; Pavuna, D.

    1991-04-01

    The evidence is reported for enhancement of critical current density J(c) in YBa2Cu3O(7-delta) thick films with the addition of Ag, which is correlated with improvements in structural properties. An improvement of 50 percent in J(c) (up to about 500 A/sq cm at T = 4.2 K) was obtained in films made from YBCO + 60 wt pct Ag powder, fabricated by the spin-on technique on (100) SrTiO3, which is correlated with improvements in structure. The resulting films are 10 microns thick, uniform, partially textured, and show good adherence. The critical temperature Tc is improved by the addition of Ag, and a reduction in the density of microcracks and in the amount of secondary phases in the sintered films was observed. Normal-state resistivity is reduced by almost three orders of magnitude, making these films potentially useful for electronic applications in interconnects and novel hybrid circuits.

  13. Examination of interfacial charge transfer in photocatalysis using patterned CuO thin film deposited on TiO2

    OpenAIRE

    Osako, K; Matsuzaki, K.; Hosono, H.; G. Yin; D. Atarashi; Sakai, E.; Susaki, T.; Miyauchi, M

    2015-01-01

    We examined the interfacial charge transfer effect on photocatalysts using a patterned CuO thin film deposited on a rutile TiO2 (110) substrate. Photocatalytic activity was visualized based on the formation of metal Ag particles resulting from the photoreduction of Ag+ ions under visible-light illumination. Ag particles were selectively deposited near the edge of CuO film for several nanometer thick CuO film, indicating that interfacial excitation from the valence band maximum of TiO2 to the ...

  14. Mechanism for silicide formation in Ag(Cu)/Si and Ag(Co)/Si upon annealing

    International Nuclear Information System (INIS)

    Ag(Co) alloy and Ag(Cu) alloy films were prepared on HF-cleaned Si by using DC magnetron sputtering and were then annealed in vacuum (3 X 10-5 Torr) to investigate the effects of Co and Cu precipitation on the material properties of the Ag alloy films and on the reaction between alloy element (Co, Cu) and Si. The annealing of a Ag(Cu)/Si structure for 30 min at 200 .deg. C produced a uniform Cu3Si layer at the Ag(Cu)-Si interface, as a result of reaction of the segregated Cu with Si. This lowered the resistivity from 5.3 to 3.2 μΩ-cm, and also led to improved adhesion properties. In contrast, the annealing of a Ag(Co)/Si structure at 400 .deg. C produced a cobalt silicide in the Ag(Co) film, resulting from reaction of the diffused Si with Co precipitates, probably at the grain boundaries. The Co silicide formed at 400 .deg. C slightly increased the resistivity, which continued to decrease at temperatures of 500 .deg. C and higher. The different diffusing species in formation of Co silicide and Cu silicide may be attributed to the difference in the temperature of silicde formation and the mobility of the species.

  15. Nucleation and growth mechanism of Ag precipitates in a CuAgZr alloy

    International Nuclear Information System (INIS)

    CuAgZr alloy is a variant of the CuAg alloy that is developed for high strength and high conductivity applications. Its strengthening is accomplished mainly by the precipitation of Ag precipitates, which tend to align on {111} planes in the Cu matrix. This alignment has been reported to be caused by stacking faults on {111} planes. Contrary to these reports, this research presents evidence for Ag precipitates formation on {111} planes due to the minimization of elastic energy. The Ag precipitates were formed by clustering of Ag atoms while maintaining the fcc crystal structure of the matrix. They have faceted {111} interfaces with the matrix. The thickening of precipitates appears to be by the ledge growth mechanism, which is resulted in by misfit dislocation networks on the interface

  16. Infiltrated TiC/Cu composites

    International Nuclear Information System (INIS)

    One approach for the fabrication of ceramic-metal composites is based on the pressureless impregnation of a porous ceramic preform by a molten metal. Molten Cu does not react with TiC and the wetting angle is close to 90o. Nonetheless, molten Cu readily impregnates partially sintered TiC preforms. A model that describes the dependence of the critical contact angle for spontaneous impregnation by molten metals in partially sintered preforms on the level of densification and on the morphology of the particles was developed. For high aspect ratios of the particles forming the preform, wetting angles close to 90o still allow impregnation by the molten metal. The results of the model were confirmed by infiltration of partially sintered TiC preforms with molten Cu and by fabrication of the TiC/Cu composites with various ceramic-to metal ratios. Decreasing of the metal content in the composite from 50 vol.% to 10 vol.% leads to a hardness increase from 250 to 1800 HV, and to the decrease of the bending strength from 960 to 280 MPa. The resistivity of these TiC/Cu composites decreases from 142 ohm cm to 25 ohm cm. (author)

  17. Equilibrium adsorption isotherm studies of Cu (II) and Co (II) in high concentration aqueous solutions on Ag-TiO2-modified kaolinite ceramic adsorbents

    Science.gov (United States)

    Ajenifuja, E.; Ajao, J. A.; Ajayi, E. O. B.

    2016-03-01

    Photocatalytic ceramic adsorbents were prepared from locally sourced kaolinite clay minerals for the removal of copper and cobalt ions from high concentration aqueous solutions. The minerals were treated with mild acid before modification using silver nanoparticles sources and titanium-oxide nanoparticles. Batch adsorption experiment was carried out on the targeted ions and the results were analyzed by Langmuir and Freundlich equation at different concentrations (100-1000 mg/l). As-received raw materials do not exhibit any adsorption capacity. However, the adsorption isotherms for modified kaolinite clay ceramic adsorbents could be fitted well by the Langmuir model for Cu2+ and Co2+ with correlation coefficient (R) of up to 0.99705. The highest and lowest monolayer coverage (q max) were 93.023 and 30.497 mg/g for Cu2+ and Co2+, respectively. The separation factor (R L ) was less than one (<1), indicating that the adsorption of metal ions on modified ceramic adsorbent is favorable. The highest adsorbent adsorption capacity (K f ) and intensity (n) constants obtained from Freundlich model are 14.401 (Cu2+ on KLN-T) and 6.057 (Co2+ on KLN-T).

  18. Zr-(Cu,Ag)-Al bulk metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Q.K.; Wang, X.D.; Nie, X.P. [International Center for New-Structured Materials (ICNSM), Zhejiang University and Laboratory of New-Structured Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Zhang, G.Q. [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Ma, H. [Department of Materials, Faculty of Engineering, University of Ulm, Albert-Einstein Allee 47, D-89081 Ulm (Germany); Fecht, H.-J. [Department of Materials, Faculty of Engineering, University of Ulm, Albert-Einstein Allee 47, D-89081 Ulm (Germany); Forschungszentrum Karlsruhe, Institut fuer Nanotechnologie, Karlsruhe (Germany); Bendnarcik, J.; Franz, H. [HASYLAB am DESY, Notkestrasse 85, D-22603 Hamburg (Germany); Liu, Y.G. [Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Cao, Q.P. [International Center for New-Structured Materials (ICNSM), Zhejiang University and Laboratory of New-Structured Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Jiang, J.Z. [International Center for New-Structured Materials (ICNSM), Zhejiang University and Laboratory of New-Structured Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)], E-mail: jiangjz@zju.edu.cn

    2008-05-15

    In this paper, we report the formation of a series Zr-(Cu,Ag)-Al bulk metallic glasses (BMGs) with diameters at least 20 mm and demonstrate the formation of about 25 g amorphous metallic ingots in a wide Zr-(Cu,Ag)-Al composition range using a conventional arc-melting machine. The origin of high glass-forming ability (GFA) of the Zr-(Cu,Ag)-Al alloy system has been investigated from the structural, thermodynamic and kinetic points of view. The high GFA of the Zr-(Cu,Ag)-Al system is attributed to denser local atomic packing and the smaller difference in Gibbs free energy between amorphous and crystalline phases. The thermal, mechanical and corrosion properties, as well as elastic constants for the newly developed Zr-(Cu,Ag)-Al BMGs, are also presented. These newly developed Ni-free Zr-(Cu,Ag)-Al BMGs exhibit excellent combined properties: strong GFA, high strength, high compressive plasticity, cheap and non-toxic raw materials and biocompatible property, as compared with other BMGs, leading to their potential industrial applications.

  19. Evidence for enhancement of critical current by intergrain Ag in YBaCuO-Ag ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Dwir, B.; Affronte, M.; Pavuna, D.

    1989-07-24

    We report the evidence for enhancement of critical current density /ital J//sub /ital c// by /similar to/50%, which occurs when /similar to/10 wt. % Ag is added to Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7/minus//delta// ceramics. The maximal /ital J//sub /ital c// (/similar to/700 A/cm/sup 2/ at /ital T/=77 K) appears simultaneously with maximum YBaCuO compactness in the samples. The silver fills the intergranular space (holes) without Cu substitution, and the critical temperature /ital T//sub /ital c// is not reduced from the bulk value (/similar to/91 K). Normal-state resistivity of Ag-YBaCuO samples is decreased by an order of magnitude, and samples exhibit improved contact resistance and resistance to water. While the critical density is improved by adding /similar to/10 wt. % Ag, it decreases at higher Ag concentrations.

  20. Trapping of self-interstitials in dilute AgCu and AgZn alloys

    International Nuclear Information System (INIS)

    Dilute alloys of AgCu and AgZn have been irradiated at various temperatures within stage II and subsequently annealed up to stage III. It is inferred from the production and the recovery data that mixed dumbbells are formed above stage I which become mobile in the middle of stage II. They are retrapped by the Cu or Zn atoms to form a more stable complex like an impurity-impurity dumbbell

  1. Trapping of self-interstitials in dilute AgCu and AgZn alloys. [Electrons

    Energy Technology Data Exchange (ETDEWEB)

    Maury, F.; Lucasson, A.; Lucasson, P. (Universite Paris 11, 91 - Orsay (France))

    1984-01-01

    Dilute alloys of AgCu and AgZn have been irradiated at various temperatures within stage II and subsequently annealed up to stage III. It is inferred from the production and the recovery data that mixed dumbbells are formed above stage I which become mobile in the middle of stage II. They are retrapped by the Cu or Zn atoms to form a more stable complex like an impurity-impurity dumbbell.

  2. IMC formation on BGA package with Sn-Ag-Cu and Sn-Ag-Cu-Ni-Ge solder balls

    International Nuclear Information System (INIS)

    Solder balls were attached to the Cu/Ni-P/Au metallized BGA substrate. The two solder ball used in this study are Sn-3.2Ag-0.5Cu and Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge. The package was subjected to thermal aging at 150 deg. C for 100-1000 h in order to investigate IMC formation behavior. Cross sections and the surface of the IMC layer, revealed through etching of the unreacted solder, were inspected and analyzed with SEM and EDX. The IMCs mainly consist of two morphologies, hexagonal and whisker. The hexagonal crystal was identified as (Cu, Ni)6Sn5 and the whisker crystal is (Ni, Cu)3Sn4. The dissolution of Ni in Cu6Sn5 results in a synergistic effect that enhances the growth of the compound, and a similar effect was not observed when dissolved Cu was present in Ni3Sn4. This phenomenon is possibly due to the vacant energy band of the 3d-orbital of Ni. Ag3Sn was also detected in the solder region near the interfacial IMC. The Ag3Sn was not in direct contact with the BGA substrate

  3. Anomalous scaling of Cu-island dynamics on Ag(100)

    Energy Technology Data Exchange (ETDEWEB)

    Zaum, Christopher; Morgenstern, Karina [Institut fuer Festkoerperphysik, Gottfried Wilhelm Leibniz Universitaet, Appelstr. 2, D-30167 Hannover (Germany)

    2008-07-01

    We deposited Cu-islands containing 10 to 500 atoms on a clean Ag(100) surface at room temperature and investigated diffusion and decay of these islands with a fast scanning tunneling microscope. Islands at sizes above 80 atoms per island are adsorbed in hollow-sites. Islands at sizes below 80 atoms per island are adsorbed in bridge-sites. Diffusion and decay behavior of the hollow-site islands is similar to the behavior of both Ag-islands on Ag(100) and Cu-islands on Cu(100). In contrast, the diffusivity and the decay time of the bridge-site islands are significantly higher than any previously measured values. This indicates a novel mechanism of diffusion.

  4. Pb-free Sn-Ag-Cu ternary eutectic solder

    Science.gov (United States)

    Anderson, Iver E.; Yost, Frederick G.; Smith, John F.; Miller, Chad M.; Terpstra, Robert L.

    1996-06-18

    A Pb-free solder includes a ternary eutectic composition consisting essentially of about 93.6 weight % Sn-about 4.7 weight % Ag-about 1.7 weight % Cu having a eutectic melting temperature of about 217.degree. C. and variants of the ternary composition wherein the relative concentrations of Sn, Ag, and Cu deviate from the ternary eutectic composition to provide a controlled melting temperature range (liquid-solid "mushy" zone) relative to the eutectic melting temperature (e.g. up to 15.degree. C. above the eutectic melting temperature).

  5. Phase equilibria of the Cu-Nb-Ti system at 850 deg. C

    International Nuclear Information System (INIS)

    The phase equilibria of the Cu-Nb-Ti system at 850 deg. C were investigated by a high-efficiency diffusion couple approach. The samples were studied by means of optical microscopy, scanning electron microscopy and electron probe microanalysis. At 850 deg. C, the phase TiCu2, the stability range of which is controversial in the literature, was observed. The solubilities of Nb in Ti2Cu, TiCu and Ti3Cu4 were determined to be 3.5, 3.1 and 4.6 at.%, respectively. The solubility of Nb in TiCu4 was negligibly small. The following three-phase equilibria were observed: Ti2Cu + TiCu + (Nb,Ti), TiCu + Ti3Cu4 + (Nb,Ti) and Ti3Cu4 + TiCu4 + (Nb,Ti)

  6. Ag-Cu-Si合金的熔化特性%Melting Characterization of Ag-Cu-Si Alloys

    Institute of Scientific and Technical Information of China (English)

    罗锡明

    1999-01-01

    用DTA法测定Ag-Cu-Si合金中(CuAgx)100-y-Siy(x=10,20,30,40,50,72)及(CuSi5)-Ag 7个特定成份伪二元系的固相线、液相线.结果表明,Si含量对Ag-Cu合金液相线温度及熔化间隔Δt的影响是显著的.在研究的Si名誉含量0~10wt%,其液相线呈"V"型变化.Δt值小对于钎料合金选择和降低Ag含量是有利的.

  7. Microstructure, mechanical properties, bio-corrosion properties and antibacterial properties of Ti-Ag sintered alloys.

    Science.gov (United States)

    Chen, Mian; Zhang, Erlin; Zhang, Lan

    2016-05-01

    In this research, Ag element was selected as an antibacterial agent to develop an antibacterial Ti-Ag alloy by a powder metallurgy. The microstructure, phase constitution, mechanical properties, corrosion resistance and antibacterial properties of the Ti-Ag sintered alloys have been systematically studied by X-ray diffraction (XRD), scanning electron microscope (SEM), compressive test, electrochemical measurements and antibacterial test. The effects of the Ag powder size and the Ag content on the antibacterial property and mechanical property as well as the anticorrosion property have been investigated. The microstructure results have shown that Ti-Ag phase, residual pure Ag and Ti were the mainly phases in Ti-Ag(S75) sintered alloy while Ti2Ag was synthesized in Ti-Ag(S10) sintered alloy. The mechanical test indicated that Ti-Ag sintered alloy showed a much higher hardness and the compressive yield strength than cp-Ti but the mechanical properties were slightly reduced with the increase of Ag content. Electrochemical results showed that Ag powder size had a significant effect on the corrosion resistance of Ti-Ag sintered alloy. Ag content increased the corrosion resistance in a dose dependent way under a homogeneous microstructure. Antibacterial tests have demonstrated that antibacterial Ti-Ag alloy was successfully prepared. It was also shown that the Ag powder particle size and the Ag content influenced the antibacterial activity seriously. The reduction in the Ag powder size was benefit to the improvement in the antibacterial property and the Ag content has to be at least 3wt.% in order to obtain a strong and stable antibacterial activity against Staphylococcus aureus bacteria. The bacterial mechanism was thought to be related to the Ti2Ag and its distribution. PMID:26952433

  8. Cu-Ti Formation in Nb-Ti/Cu Superconducting Strand Monitored by in situ Techniques

    CERN Document Server

    Pong, I; Pong, Ian; Gerardin, Alexandre; Scheuerlein, Christian; Bottura, Luca

    2010-01-01

    In order to investigate the high temperature exposure effect on Nb-Ti/Cu superconducting strands, as might be encountered in joining by soldering and in cabling annealing, X-ray diffraction and resistometry measurements were performed in situ during heat treatment, and complemented by conventional metallography, mechanical tests and superconducting properties measurements. Changes of the Nb-Ti nanostructure at temperatures above 300 degrees C are manifested in the degradation of critical current in an applied external magnetic field, although degradation at self field was insignificant up to 400 degrees C for several minutes. Above 500 degrees C, the formation of various Cu-Ti intermetallic compounds, due to Ti diffusion from Nb-Ti into Cu, is detected by in situ XRD albeit not resolvable by SEM-EDS. There is a ductile to brittle transition near 600 degrees C, and liquid formation is observed below 900 degrees C. The formation of Cu-Ti causes a delayed reduction of the residual resistivity ratio (RRR) and adv...

  9. Electrochemical synthesis of fractal bimetallic Cu/Ag nanodendrites for efficient surface enhanced Raman spectroscopy.

    Science.gov (United States)

    Li, Da; Liu, Jingquan; Wang, Hongbin; Barrow, Colin J; Yang, Wenrong

    2016-09-21

    Here, we for the first time synthesized bimetallic Cu/Ag dendrites on graphene paper (Cu/Ag@G) using a facile electrodeposition method to achieve efficient SERS enhancement. Cu/Ag@G combined the electromagnetic enhancement of Cu/Ag dendrites and the chemical enhancement of graphene. SERS was ascribed to the rough metal surface, the synergistic effect of copper and silver nanostructures and the charge transfer between graphene and the molecules. PMID:27522964

  10. Microstructure of electroplated Cu(Ag) alloy thin films

    International Nuclear Information System (INIS)

    Electroplated Cu(Ag) alloy thin films are potential candidates for future electronic devices in terms of lifetime and reliability compared to copper as the state of the art interconnect material. In the present paper we focus on the microstructure of Cu(Ag) alloy films considering the grain evolution as well as silver incorporation and segregation. We show that Ag alloying addition prevents room temperature recrystallization. Thermally induced grain growth occurs mainly between 180 oC and 330 oC. Silver can be incorporated as solid solution into the Cu matrix by up to 0.8 at.% after annealing and even in higher concentrations in the as-deposited state, which is significantly above the equilibrium solubility limit. Precipitations are formed by the continuous mode and can be mainly found at the film surface but also inside the Cu(Ag) grains as ball-shaped particles. Based on our results a reliability improvement is expected by mechanical strengthening due to alloying effects while maintaining a low electrical resistivity and a {111} fiber texture.

  11. The role of Ag in (Ag,Cu)2ZnSnS4 thin film for solar cell application

    International Nuclear Information System (INIS)

    Highlights: • (Ag,Cu)2ZnSnS4 thin film was synthesized through metallic stacking layers. • Ag incorporation reduces the size and amount of voids at back contact. • Less planar defects and Cu vacancy are formed in the (Ag,Cu)2ZnSnS4. • Solar cell performance was improved with Ag incorporation. - Abstract: Recently, Ag incorporation into Cu(In,Ga)Se2 structure was found to benefit the solar cell performance. However, (Ag,Cu)2ZnSnS4 used as the solar cell absorber is not widely reported even though Ag2ZnSnS4 has shown much better photocatalysts activity for H2 evolution than Cu2ZnSnS4. In this paper, (Ag,Cu)2ZnSnS4 thin film solar cell was synthesized through sulfurization of Ag/Zn/Cu/Sn metallic stacked layers. In order to understand the actual role of Ag in the Cu2ZnSnS4 structure, the changing chemical environment, microstructure and intragrain defect due to the Ag incorporation, were studied by X-ray photoelectron spectroscopy and transmission electron microscopy. After sulfurization, Ag is uniformly distributed in the absorber and is incorporated into Cu2ZnSnS4 crystal structure but no obvious change of the Cu2ZnSnS4 chemical environment is detected. A large density of voids is formed at the Cu2ZnSnS4/Mo interface and some of these voids are found to be coated with CdS which is believed to be detrimental to Cu2ZnSnS4 device performance. In contrast, Ag incorporation reduces the size and amount of voids and thus effectively eliminates CdS deposited at back contact region. Moreover, fewer planar defects and Cu vacancies are formed in the (Ag,Cu)2ZnSnS4 sample than Cu2ZnSnS4 sample as suggested by electron diffraction patterns. Therefore, improved solar cell performance should result from the formation of (Ag,Cu)2ZnSnS4 structure

  12. Photocatalysis/catalysis by innovative TiN and TiN-Ag surfaces inactivate bacteria under visible light

    OpenAIRE

    Rtimi, Sami; Baghriche, Oualid; Sanjines, Rosendo; Pulgarin, César; Ben-Simon, Michaël; Lavanchy, J.-C.; Houas, A.; Kiwi, John

    2012-01-01

    This study presents the design, preparation, testing and characterization of TiN and TiN-Ag nanoparticulate films leading to photocatalytic and catalytic inactivation of Escherichia coli. When Ti was sputtered in N2 atmosphere, the TiN films unexpectedly revealed semiconductor properties when irradiated under visible light due to the formation of TiO2 showing absorption in the visible spectral region. In TiN-Ag films, Ag enhances the photocatalytic activity of TiN leading to faster bacterial ...

  13. Diffusion of Cu adatoms and dimers on Cu(111) and Ag(111) surfaces

    Science.gov (United States)

    Mińkowski, Marcin; Załuska-Kotur, Magdalena A.

    2015-12-01

    Diffusion of Cu adatoms and dimers on Cu(111) and Ag(111) surfaces is analyzed based on ab initio surface potentials. Single adatom diffusion is compared with dimer diffusion on both surfaces. Surface geometry makes the adatoms jump alternately between two states in the same way in both systems, whereas dimers undergo more complex diffusion process that combines translational and rotational motion. Small difference in the surface lattice constant between Cu and Ag crystals results in a completely different energy landscape for dimer jumps. As an effect the character of diffusion process changes. Homogeneous Cu dimer diffusion is more difficult and dimers rather rotate within single surface cell, whereas diffusion over Ag surface is faster and happens more smoothly. The temperature dependence of diffusion coefficient and its parameters: energy barrier and prefactor is calculated and compared for both surfaces.

  14. Microstructural and auger microanalytical characterization of Cu-Hf and Cu-Ti catalysts.

    Science.gov (United States)

    Pisarek, M; Janik-Czachor, M

    2006-06-01

    Degradation processes occurring at the surface and in the bulk of Cu-based amorphous alloys during cathodic hydrogen charging were used for promoting the catalytic activity of such alloys. These processes modifying the structure, composition, and morphology of the substrate proved to be useful methods for transforming Cu-Hf and inactive Cu-Ti amorphous alloy precursors into active and durable catalysts. Indeed, their catalytic activity for dehydrogenation of 2-propanol increased up to a conversion level of approximately 60% at selectivities to acetone of about 99% for Cu-Ti and to conversion of approximately 90% at selectivities of approximately 95% for Cu-Hf. Previous attempts carried out by aging in air or hydrogen charging from the gas phase resulted in a maximum conversion level up to 15% for Cu-Hf and up to 3% for Cu-Ti. High resolution Auger spectroscopy allowed changes occurring during the activation process to be identified, namely, the formation of small Cu particles on the HfO2 surface and the formation of highly porous particles containing mostly Cu and some Ti and O (Cu-Ti-O) on a Cu-Ti substrate. Differences in the chemistry and structure of both catalysts are discussed, and the implications for catalytic function are considered. A probable configuration of active sites on the Cu-Ti-O/Ti-O-Cu catalyst for dehydrogenation of 2-propanol is proposed. PMID:17481359

  15. Microgalvanic Corrosion Behavior of Cu-Ag Active Braze Alloys Investigated with SKPFM

    Directory of Open Access Journals (Sweden)

    Armen Kvryan

    2016-04-01

    Full Text Available The nature of microgalvanic couple driven corrosion of brazed joints was investigated. 316L stainless steel samples were joined using Cu-Ag-Ti and Cu-Ag-In-Ti braze alloys. Phase and elemental composition across each braze and parent metal interface was characterized and scanning Kelvin probe force microscopy (SKPFM was used to map the Volta potential differences. Co-localization of SKPFM with Energy Dispersive Spectroscopy (EDS measurements enabled spatially resolved correlation of potential differences with composition and subsequent galvanic corrosion behavior. Following exposure to the aggressive solution, corrosion damage morphology was characterized to determine the mode of attack and likely initiation areas. When exposed to 0.6 M NaCl, corrosion occurred at the braze-316L interface preceded by preferential dissolution of the Cu-rich phase within the braze alloy. Braze corrosion was driven by galvanic couples between the braze alloys and stainless steel as well as between different phases within the braze microstructure. Microgalvanic corrosion between phases of the braze alloys was investigated via SKPFM to determine how corrosion of the brazed joints developed.

  16. Microstructure of Cu-Ag Uniform Nanoparticulate Films on Polyurethane 3D Catheters: Surface Properties.

    Science.gov (United States)

    Rtimi, Sami; Sanjines, Rosendo; Pulgarin, Cesar; Kiwi, John

    2016-01-13

    The preparation, characterization, and antibacterial testing of Cu-Ag sputtered polyurethane (PU) catheters are addressed in this study. PU catheters with different atomic ratios Cu:Ag have been sputtered and led to different optical properties as followed by diffuse reflectance spectroscopy (DRS) and the surface redox properties were also different for different Cu-Ag ratios as observed by X-ray photoelectron spectroscopy (XPS). The surface atomic percentage concentration of the oxidized/reduced C-species originating from bacterial cultures before and after bacterial inactivation were determined on the Cu-Ag PU catheters. The crystallographic properties were determined by X-ray diffraction (XRD). The XRD-diffractogram showed the presence of Cu2O (111), Cu (200), CuO (020), and Ag (111) indicating that Cu nanoparticles present a more crystalline character compared to Ag nanoparticles. Increasing the percentage of Ag in the Cu-Ag films, bigger Ag-particle agglomerates were detected by scanning transmission electron microscopy (STEM) microanalysis confirming the results obtained by AFM. The bacterial inactivation kinetics of the sputtered Cu-Ag films on PU catheters was investigated in detail. Quasi-instantaneous bacterial inactivation kinetics was induced by the sputtered films on PU catheters after optimization of the Cu-Ag film thickness. PMID:26700113

  17. Electrochemical behavior of Ag-Cu alloy in alkaline media

    Directory of Open Access Journals (Sweden)

    Grekulović Vesna J.

    2010-01-01

    Full Text Available Results of the investigation of electrochemical behaviour of Ag-Cu alloy containing 50 mass% Ag and 50 mass% Cu are presented in this paper. Pure silver and copper were investigated, too. Working electrodes were prepared by metallurgical process. 1 mol dm-3 and 0.5 mol dm-3 solutions of NaOH are chosen as the electrolyte. On the cyclic voltammograms, some current waves corresponding to number and quantity of phases present in the investigated electrodes appeared and they can be used for characterization of investigated alloy. On the voltammogram recorded for pure silver, two anodic and two cathodic peaks appeared. First peak consisted of two joined current waves which can be ascribed to the formation of the two different types of silver(I oxide, Ag2O. Second peak should correspond to the formation of silver(II oxide, AgO. Voltammogram obtained for pure copper exhibits one broad current wave corresponding to the formation of copper oxides, followed by a wide potential area in which copper is completely passive. At 0.4 V vs. SCE, current starts to increase again due to oxygen evolution and probably due to simultaneous dissolution of copper with formation of CuO22- as a product. In alkaline solutions copper has no significant influence on the shape and current values of the voltammograms recorded for Ag-Cu alloy; however, it has an influence only on the anodic and cathodic peak potentials, which are shifted to more negative values in comparison to Ag. It could mean an easier formation of oxides and their harder reduction. Comparing voltammograms recorded for Ag-Cu alloy in 0.5 moldm-3 NaOH and in 1 moldm-3 NaOH solutions, one can see that current waves appear at more positive potentials on the voltammograms obtained in the solution of lower concentration and with much higher current densities than those on the voltammograms obtained in the solution of higher concentration.

  18. Ti-Ag-Pd alloy with good mechanical properties and high potential for biological applications.

    Science.gov (United States)

    Zadorozhnyy, V Yu; Shi, X; Gorshenkov, M V; Kozak, D S; Wada, T; Louzguine-Luzgin, D V; Inoue, A; Kato, H

    2016-01-01

    Ti-based alloys containing Ag were produced by tilt-casting method and their properties were studied. Even in its as-cast state, Ti94Ag3Pd3 showed relatively high tensile properties, good electrochemical behavior, and good biocompatibility. The relatively good mechanical properties of the as-cast α-Ti-type Ti94Ag3Pd3 alloy (tensile strength up to 850 MPa and elongation of ~10%) can be explained by its severely deformed, fine crystalline structure. The high biocompatibility of Ti94Ag3Pd3 can be explained by the Ag-Pd interaction, which inhibits the release of Ag ions from the surface. Ag, in combination with Pd has no toxic effects and demonstrates useful antimicrobial properties. The Ti94Ag3Pd3 alloy shows a good potential to be applied as a biomedical implant alloy. PMID:27122177

  19. Surface Characterization and Cell Response of Binary Ti-Ag Alloys with CP Ti as Material Control

    Institute of Scientific and Technical Information of China (English)

    B.B. Zhang; K.J. Qiu; B.L. Wang; L. Li; Y.F. Zheng

    2012-01-01

    In this study, the surface passive films, dissolution behavior and biocompatibility of Ti-Ag alloys (with 5%, 10% and 20% Ag) were evaluated by X-ray diffraction (XRD) tests, electrochemical corrosion tests, X-ray photoelectron spectroscopy (XPS) tests, dissolution tests and in-vitro cytotoxicity tests. The surface films on the Ti-20Ag alloy are rich in Ti and much deficient in Ag with respect to alloy composition, as identified by XPS. Compared to CP Ti, Ti-SAg and Ti-20Ag alloys show larger impedances and lower capacitances, which can be associated with an increase of the passive layer thickness. Moreover, all Ti-Ag alloys exhibit negligible or low metal release in the test solutions. The in-vitro cytotoxicity results show Ti-Ag alloys seem to be as cytocompatible as CP Ti. From the viewpoint of surface passive film and cytotoxicity, Ti-SAg and Ti-20Ag are considered to be more suitable for dental applications.

  20. Au-Ag-Cu nano-alloys: tailoring of permittivity

    Science.gov (United States)

    Hashimoto, Yoshikazu; Seniutinas, Gediminas; Balčytis, Armandas; Juodkazis, Saulius; Nishijima, Yoshiaki

    2016-04-01

    Precious metal alloys enables new possibilities to tailor materials for specific optical functions. Here we present a systematic study of the effects of a nanoscale alloying on the permittivity of Au-Ag-Cu metals at 38 different atomic mixing ratios. The permittivity was measured and analyzed numerically by applying the Drude model. X-ray diffraction (XRD) revealed the face centered cubic lattice of the alloys. Both, optical spectra and XRD results point towards an equivalent composition-dependent electron scattering behavior. Correlation between the fundamental structural parameters of alloys and the resulting optical properties is elucidated. Plasmonic properties of the Au-Ag-Cu alloy nanoparticles were investigated by numerical simulations. Guidelines for designing plasmonic response of nano- structures and their patterns are presented from the material science perspective.

  1. Au-Ag-Cu nano-alloys: tailoring of permittivity

    Science.gov (United States)

    Hashimoto, Yoshikazu; Seniutinas, Gediminas; Balčytis, Armandas; Juodkazis, Saulius; Nishijima, Yoshiaki

    2016-01-01

    Precious metal alloys enables new possibilities to tailor materials for specific optical functions. Here we present a systematic study of the effects of a nanoscale alloying on the permittivity of Au-Ag-Cu metals at 38 different atomic mixing ratios. The permittivity was measured and analyzed numerically by applying the Drude model. X-ray diffraction (XRD) revealed the face centered cubic lattice of the alloys. Both, optical spectra and XRD results point towards an equivalent composition-dependent electron scattering behavior. Correlation between the fundamental structural parameters of alloys and the resulting optical properties is elucidated. Plasmonic properties of the Au-Ag-Cu alloy nanoparticles were investigated by numerical simulations. Guidelines for designing plasmonic response of nano- structures and their patterns are presented from the material science perspective. PMID:27118459

  2. Au-Ag-Cu nano-alloys: tailoring of permittivity.

    Science.gov (United States)

    Hashimoto, Yoshikazu; Seniutinas, Gediminas; Balčytis, Armandas; Juodkazis, Saulius; Nishijima, Yoshiaki

    2016-01-01

    Precious metal alloys enables new possibilities to tailor materials for specific optical functions. Here we present a systematic study of the effects of a nanoscale alloying on the permittivity of Au-Ag-Cu metals at 38 different atomic mixing ratios. The permittivity was measured and analyzed numerically by applying the Drude model. X-ray diffraction (XRD) revealed the face centered cubic lattice of the alloys. Both, optical spectra and XRD results point towards an equivalent composition-dependent electron scattering behavior. Correlation between the fundamental structural parameters of alloys and the resulting optical properties is elucidated. Plasmonic properties of the Au-Ag-Cu alloy nanoparticles were investigated by numerical simulations. Guidelines for designing plasmonic response of nano- structures and their patterns are presented from the material science perspective. PMID:27118459

  3. New Cu-Free Ti-Based Composites with Residual Amorphous Matrix

    OpenAIRE

    Mircea Nicoara; Cosmin Locovei; Viorel Aurel Șerban; R. Parthiban; Mariana Calin; Mihai Stoica

    2016-01-01

    Titanium-based bulk metallic glasses (BMGs) are considered to have potential for biomedical applications because they combine favorable mechanical properties and good biocompatibility. Copper represents the most common alloying element, which provides high amorphization capacity, but reports emphasizing cytotoxic effects of this element have risen concerns about possible effects on human health. A new copper-free alloy with atomic composition Ti42Zr10Pd14Ag26Sn8, in which Cu is completely rep...

  4. Properties of Cu film and Ti/Cu film on polyimide prepared by ion beam techniques

    International Nuclear Information System (INIS)

    Cu film and Ti/Cu film on polyimide substrate were prepared by ion implantation and ion beam assisted deposition (IBAD) techniques. Three-dimension white-light interfering profilometer was used to measure thickness of each film. The thickness of the Cu film and Ti/Cu film ranged between 490 nm and 640 nm. The depth profile, surface morphology, roughness, adhesion, nanohardness, and modulus of the Cu and Ti/Cu films were measured by scanning Auger nanoprobe (SAN), atomic force microscopy (AFM), and nanoindenter, respectively. The polyimide substrates irradiated with argon ions were analyzed by scanning electron microscopy (SEM) and AFM. The results suggested that both the Cu film and Ti/Cu film were of good adhesion with polyimide substrate, and ion beam techniques were suitable to prepare thin metal film on polyimide.

  5. Damage behavior of SnAgCu/Cu solder joints subjected to thermomechanical cycling

    International Nuclear Information System (INIS)

    Highlights: •A creep–fatigue damage model based on CDM was proposed. •Designed system includes load frame, strain measure device and damage test device. •Damage evolution of solder joints was a function of accumulated inelastic strain. •Damage of solder joints is an interaction between creep and low-cycle fatigue. -- Abstract: Thermomechanical fatigue damage is a progressive process of material degradation. The objective of this study was to investigate the damage behavior of SnAgCu/Cu solder joints under thermomechanical cycling. A damage model was proposed based on continuum damage mechanics (CDM). Based upon an analysis of displacements for flip-chip solder joints subjected to thermal cycling, a special bimetallic loading frame with single-solder joint samples was designed to simulate the service conditions of actual joints in electronic packages. The assembly, which allowed for strain measurements of an individual solder joint during temperature cycling, was used to investigate the impact of stress–strain cycling on the damage behavior of SnAgCu/Cu solder joints. The characteristic parameters of the damage model were determined through thermomechanical cycling and strain measurement tests. The damage variable D = 1 − R0/R was selected, and values for it were obtained using a four-probe method for the single-solder joint samples every dozen cycles during thermomechanical cycling tests to verify the model. The results showed that the predicted damage was in good agreement with the experimental results. The damage evolution law proposed here is a function of inelastic strain, and the results showed that the damage rate of SnAgCu/Cu solder joints increased as the range of the applied strain increased. In addition, the microstructure evolution of the solder joints was analyzed using scanning electron microscopy, which provided the microscopic explanation for the damage evolution law of SnAgCu/Cu solder joints

  6. Characteristics Of Sn-Zn Cast Alloys With The Addition Of Ag And Cu

    OpenAIRE

    Gancarz T.; Pstruś J.

    2015-01-01

    The aim of this work was to study the effects of Ag and Cu on the thermal properties and microstructure of Sn-Zn-Ag-Cu cast alloys. Solders based on eutectic Sn-Zn containing 0.5 to 1.0 at.% of Ag and Cu were developed for wave soldering. DSC measurements were performed to determine the melting temperatures of the alloys. TMA and electrical resistivity measurements were performed between −50 and 150°C and between 30 and 150°C, respectively. Small precipitates of Cu5Zn8, CuZn4, and AgZn3 were ...

  7. Effect of Ti3+ on TiO2-supported Cu catalysts used for CO oxidation.

    Science.gov (United States)

    Chen, Ching S; Chen, Tse C; Chen, Chen C; Lai, Yuan T; You, Jiann H; Chou, Te M; Chen, Ching H; Lee, Jyh-Fu

    2012-07-01

    In this paper, we have shown that Cu/TiO(2) catalysts are highly active in CO oxidation. For instance, a 3.4% Cu/TiO(2) catalyst exhibits a higher turnover rate for the effective removal of CO in air than 3-5% Pt/TiO(2) and 20% Cu/ZnO/Al(2)O(3) catalysts. A small amount of Cu(+) species is formed during the calcination treatment at 225 °C, which is the main active phase for the CO oxidation. However, it is proposed that some highly dispersed CuO can also form in the TiO(2) lattice during the calcination treatment. Furthermore, a strong electron interaction between Cu(2+) in highly dispersed CuO and Ti(3+) on rutile TiO(2) (Cu(2+)+Ti(3+)→Cu(+)+Ti(4+)) has been shown to occur. Overall, the reduction of Cu(+) is a major factor that contributes to the reaction rate of the CO oxidation. PMID:22676402

  8. Interface evolution of TiAl/Ti6242 transient liquid phase joint using Ti, Cu foils as insert metals

    Institute of Scientific and Technical Information of China (English)

    DUAN Hui-ping; K. H. Bohm; V. Ventzke; M. Kocak

    2005-01-01

    The interface evolution of TiAl/Ti6242 joint produced by transient liquid phase(TLP) bonding with Ti,Cu foils as insert metals was investigated. The results show that the surface oxide layer on TiAl plays a very imporer on the surface of TiAl. The diffusion behavior of Cu atoms in TiAl is strongly controlled by the vacancies beneath the surface of TiAl. Based on the interface diffusion and interface wettability, a mechanism for the effect of bonding pressure, bonding temperature, holding time and stacking sequence of the insert foils on the joint formation process were proposed.

  9. Highly efficient and stable Ag-AgBr/TiO2 composites for destruction of Escherichia coli under visible light irradiation.

    Science.gov (United States)

    Wang, Xiaoping; Lim, Teik-Thye

    2013-08-01

    A series of Ag-AgBr/TiO2 composites were prepared by a sol-gel method followed by photoreduction. Effect of Ag-AgBr content on the physicochemical properties and antibacterial activities of the Ag-AgBr/TiO2 composites was investigated. These composites showed intrinsic antibacterial activities against Escherichia coli (E. coli) in the dark attributed to the Ag nanoparticles dispersed in the composites. Under visible light irradiation, inactivation of E. coli over these Ag-AgBr/TiO2 composites was attributed to both their photocatalytic disinfection activities and intrinsic antibacterial properties. The Ag-AgBr/TiO2 with an optimum Ti/Ag atomic ratio of 10 exhibited superior visible-light photocatalytic activities for ibuprofen degradation and mineralization as compared to the other Ag-AgBr/TiO2 composites and also Ag-AgBr/P25, Ag/TiO2 and TiO2. It is probably because of the coexistence of two visible-light active components (AgBr and Ag nanoparticles) and the most effective separation of photogenerated electrons and holes in this photocatalyst. Correspondingly, the photocatalyst achieved a much higher efficiency of E. coli destruction than Ag-AgBr/P25 and TiO2. E. coli was almost completely inactivated (7-log reduction) within 60 min by the photocatalyst with a rather low dosage of 0.05 g L(-1) under white LED irradiation. Furthermore, the Ag-AgBr/TiO2 showed high stability for photocatalytic destruction of E. coli and the dark repair and photoreactivation did not occur after the photocatalytic process. Finally, the action spectrum of this photocatalyst for E. coli inactivation and the influence of several inorganic ions present in surface water were also investigated. PMID:23562562

  10. Electron channeling in TiO2 coated Cu layers

    Science.gov (United States)

    Zheng, Pengyuan; Zhou, Tianji; Gall, Daniel

    2016-05-01

    Electron transport in metal conductors with ∼5–30 nm width is dominated by surface scattering. In situ transport measurements as a function of surface chemistry demonstrate that the primary parameter determining the surface scattering specularity is the localized surface density of states at the Fermi level N(E f ). In particular, the measured sheet resistance of epitaxial Cu(001) layers with thickness d Cu = 9–25 nm increases when coated with d Ti = 0.1–4.0 monolayers (MLs) of Ti, but decreases again during exposure to 37 Pa of O2. These resistivity changes are a function of d Cu and d Ti and are due to a transition from partially specular electron scattering at the Cu surface to completely diffuse scattering at the Cu–Ti interface, and the recovery of surface specularity as the Ti is oxidized. X-ray reflectivity and photoelectron spectroscopy indicate the formation of a 0.47 ± 0.03 nm thick Cu2O surface layer on top of the TiO2–Cu2O during air exposure, while density functional calculations of TiO x cap layers as a function of x = 0–2 and d Ti = 0.25–1.0 ML show a reduction of N(E f ) by up to a factor of four. This reduction is proposed to be the key cause for the recovery of surface specularity and results in electron confinement and channeling in the Cu layer upon Ti oxidation. Transport measurements at 293 and 77 K confirm the channeling and demonstrate the potential for high-conductivity metal nanowires by quantifying the surface specularity parameter p = 0.67 ± 0.05, 0.00 ± 0.05, and 0.35 ± 0.05 at the Cu–vacuum, Cu–Ti, and Cu–TiO2 interfaces.

  11. Electrochemical sensing and photocatalysis using Ag-TiO2 microwires

    Indian Academy of Sciences (India)

    Soumit S Mandal; Aninda J Bhattacharyya

    2012-09-01

    Anatase Ag-TiO2 microwires with high sensitivity and photocatalytic activity were synthesized via polyol synthesis route followed by a simple surface modification and chemical reduction approach for attachment of silver. The superior performance of the Ag-TiO2 composite microwires is attributed to improved surface reactivity, mass transport and catalytic property as a result of wiring the TiO2 surface with Ag nanoparticles. Compared to the TiO2 microwires, Ag-TiO2 microwires exhibited three times higher sensitivity in the detection of cationic dye such as methylene blue. Photocatalytic degradation efficiency was also found to be significantly enhanced at constant illumination protocols and observation times. The improved performance is attributed to the formation of a Schottky barrier between TiO2 and Ag nanoparticles leading to a fast transport of photogenerated electrons to the Ag nanoparticles.

  12. Synthesis of MOF templated Cu/CuO@TiO2 nanocomposites for synergistic hydrogen production.

    Science.gov (United States)

    Mondal, Indranil; Pal, Ujjwal

    2016-02-14

    A copper metal-organic framework (Cu-MOF) provides access to Cu/CuO@TiO2 hybrid nanocomposites with highly dispersive copper species adsorbed on a TiO2 semiconducting system. This novel nanostructure exhibits efficient hydrogen evolution performance under solar illumination of intensity ∼1 Sun. The rate of H2 production was systematically optimized under different operational parameters. Experimental observation reveals that mesoporous Cu/CuO@TiO2 nanocomposite with 0.5 wt% Cu loading showed the highest rate of H2 production (286 mmol g(-1) h(-1)), which is considerably higher than that of CuO loaded TiO2 prepared using a conventional impregnation method. This high photocatalytic H2 production activity is attributed predominantly to the presence of surface deposited Cu(0) species and the small size of the heterojunction (1-2 nm) between CuO and TiO2, which facilitate interfacial charge carrier transfer from the TiO2 nanoparticles. The catalyst showed good recyclability under prolonged exposure (30 h) to solar irradiation. Unlike many Pt decorated TiO2 photocatalysts, this hybrid photocatalyst provides an inexpensive means of harnessing solar energy. PMID:26806274

  13. Interplay between structural symmetry and magnetism in Ag-Cu

    Science.gov (United States)

    Yen, Tsung-Wen; Lai, S. K.

    2016-01-01

    We present first-principles theoretical calculations of the magnetic properties of bimetallic clusters Ag-Cu. The calculations proceeded by combining a previously developed state-of-the-art optimization algorithm (P.J. Hsu, S.K. Lai, J. Chem. Phys. 124 (2006) 0447110) with an empirical potential and applied this numerical scheme to determine first the lowest energy structures of pure clusters Ag38 and Cu38, and also their different atomic compositions AgnCu38-n for n=1,2,…,37. Then, we carried out the Kohn-Sham spin unrestricted density functional theory calculations on the optimized atomic structures obtained in the preceding step. Given the minimized structures from the first step as input configurations, the results of these re-optimized structures by full density functional theory calculations yield more refined electronic and atomic structures. A thorough comparison of the structural differences between these two sets of atomic geometries, one from using an empirical potential in which the electronic degrees of freedom were included approximately and another from subsequent minimization using the spin unrestricted density functional theory, sheds light on how the electronic charges disperse near atoms in clusters AgnCu38-n, and hence the distributions of electronic spin and charge densities at re-optimized sites of the cluster. These data of the electronic dispersion and the ionic configuration give clue to the mystery of the unexpected net magnetic moments which were found in some of the clusters AgnCu38-n at n=1-4, 24 as well as the two pure clusters. Possible origins for this unanticipated magnetism were explained in the context of the point group theory in much the same idea as the Clemenger-Nilsson model applied to simple metal clusters except that we draw particular attention to the atomic topologies and stress the bearing that they have on valence electrons in inducing them to disperse and occupy different molecular orbital energy levels.

  14. New Ti-based Ti–Cu–Zr–Fe–Sn–Si–Ag bulk metallic glass for biomedical applications

    International Nuclear Information System (INIS)

    Highlights: • Novel Ti47Cu38Zr7.5Fe2.5Sn2Si1Ag2 (at.%) bulk metallic glass (BMG) with a critical diameter of 7 mm was discovered. • The present BMG is the largest Ni- and Be-free Ti-based BMG containing low content of noble metal reported to date. • The glassy alloy possesses high specific strength, low Young’s modulus, and good corrosion resistance and bio-compatibility. • Combination of high glass-forming ability and good mechano- and bio-compatibility for the Ti-based BMG demonstrates the potential for use in biomedical applications. - Abstract: A novel Ni-free Ti47Cu38Zr7.5Fe2.5Sn2Si1Ag2 (at.%) bulk metallic glass (BMG) with superior glass-forming ability, good mechanical properties and excellent biocompatibility was discovered. The Ti-based BMG with a diameter of 7 mm can be prepared by copper mold casting and the supercooled liquid region was 52 K. Compressive strength, specific strength, Young’s modulus and microhardness of the Ti-based BMG were about 2.08 GPa, 3.2 × 105 N m/kg, 100 GPa and 588 Hv, respectively. Electrochemical measurements indicated that the Ti-based glassy alloy possesses higher corrosion resistance than Ti–6Al–4V alloy in a simulated body fluid environment. Attachment, spreading out and proliferation of MC3T3-E1 cells on the Ti-based BMG surface demonstrated the excellent biocompatibility. Mechanisms of the formation and properties for the Ti-based glassy alloy are also discussed. The combination of high glass-forming ability, excellent mechanical properties, high corrosion resistance and good biocompatibility demonstrates the potential of the Ni-free Ti-based BMG for use in biomedical applications

  15. Low temperature properties of organicinorganic Ag/p-CuPc/n-GaAs/Ag photoelectric sensor

    Institute of Scientific and Technical Information of China (English)

    Kh.; S.; KARIMOV; I.; QAZI; T.; A.; KHAN; M.; I.; FEDOROV

    2008-01-01

    A thin organic film of p-type semiconducting copper phthalocynanine (CuPc) was deposited by vacuum evaporation on an n-type GaAs single-crystal semiconductor substrate. The fabricated Ag/p-CuPc/n-GaAs/Ag sensor was carried through an ageing process to stabilize the parameters. Voltage-current characteristics and photoelectrical response of the sensor were investigated at a wide temperature range of 82 to 350 K. Photoelectric characteristics were measured under non-modulated filament-lamp illumination. It was observed that such sensor parameters as rectification ratio,threshold voltage,junction,shunt and series resistances,open-circuit voltage and short circuit current are temperature-dependent. It was found that wide-range voltage-current characteristics of the sensor may be de-scribed similarly to that of a Schottky barrier diode. Using the experimental data on voltage-current characteristics and absorbance of the CuPc films,the energy-band diagram of the p-CuPc/n-GaAs heterojunction was developed. It was shown that data obtained from simulation of an equivalent circuit of photoelectric sensor agreed with experimental results.

  16. Cytotoxicity of serum protein-adsorbed visible-light photocatalytic Ag/AgBr/TiO2 nanoparticles

    International Nuclear Information System (INIS)

    Highlights: ► Photocytotoxicity of visible-light catalytic NPs was examined in vitro. ► Ag/AgBr/TiO2 NPs were well internalized in cells after adsorption of serum proteins. ► Cell viability was decreased by 40–60% using ∼8 ppm NPs and 60 W/cm2 visible light within 5 h. ► Mitochondria activity test indicated the reactive oxygen species for photo-destruction of cells. ► Ag/AgBr/TiO2 NPs were found to eliminate xenograft tumors significantly in vivo. - Abstract: Photocytotoxicity of visible-light catalytic Ag/AgBr/TiO2 nanoparticles (NPs) was examined both in vitro and in vivo. The Ag/AgBr/TiO2 NPs were prepared by the deposition–precipitation method. Their crystalline structures, atomic compositions, and light absorption property were examined by X-ray diffraction (XRD) patterns, X-ray photoelectron (XPS) intensities, and ultraviolet-visible (UV–vis) diffuse reflectance spectroscopic tools. The Ag/AgBr/TiO2 NPs appeared to be well internalized in human carcinoma cells as evidenced by transmission electron microscopy (TEM). The cytotoxicity of cetylmethylammonium bromide (CTAB) appeared to be significantly reduced by adsorption of serum proteins in the cellular medium on the NP surfaces. Two types of human cervical HeLa and skin A431 cancer cells were tested to check their viability after the cellular uptake of the Ag/AgBr/TiO2 NPs and subsequent exposure to an illumination of visible light from a 60 W/cm2 halogen lamp. Fluorescence images taken to label mitochondria activity suggest that the reactive oxygen species should trigger the photo-destruction of cancer cells. After applying the halogen light illumination for 50–250 min and ∼8 ppm (μg/mL) of photocatalytic Ag/AgBr/TiO2 NPs, we observed a 40–60% selective decrease of cell viability. Ag/AgBr/TiO2 NPs were found to eliminate xenograft tumors significantly by irradiating visible light in vivo for 10 min.

  17. Optical Limiting Properties of Ag-Cu Metal Alloy Nanoparticles Analysis by using MATLAB

    International Nuclear Information System (INIS)

    Ag-Cu alloy nanoparticles were formed by sequential ion implantation (Ag and Cu) in silica using a metal vapor vacuum arc (MEVVA) ion source. Third-order nonlinear optical properties of the nanoparticles were measured at 1064 nm excitations using the Z-scan technique. Curve fitting analysis, based on the MATLAB features for Ag-Cu alloy nanoparticle optical limiting experiments, is used. The results show that Ag-Cu alloy nanoparticles display a refractive optical limiting effect at 1064nm. (condensed matter: structure, mechanical and thermal properties)

  18. Structures and segregation patterns of Ag-Cu and Ag-Ni nanoalloys adsorbed on MgO(0 0 1).

    Science.gov (United States)

    Bochicchio, Davide; Ferrando, Riccardo; Panizon, Emanuele; Rossi, Giulia

    2016-02-17

    Low-energy geometric structures and segregation patterns of Ag-Cu and Ag-Ni nanoparticles adsorbed on MgO(0 0 1) are searched for by global optimisation methods within an atomistic potential model. Sizes betwen 100 and 300 atoms are considered for several compositions. In all cases, Ag segregates to the nanoparticle surface, so that Cu@Ag and Ni@Ag core-shell arrangements are found, with off-centre cores for Ag-rich compositions. The behaviours of Ag-Cu and Ag-Ni differ at the interface with the MgO substrate. For Ag-Cu, some Cu atoms are at the interface even for compositions that are very rich in Ag, where Ag-Ni nanoparticles present an interface completely made of Ag atoms. Ag-Ni and Ag-Cu also differ concerning their geometric structures. With increasing Ag content, in Ag-Cu we find the structural sequence faulted fcc [Formula: see text] icosahedral [Formula: see text] fcc, while in Ag-Ni we find the sequence hcp [Formula: see text] faulted fcc-faulted hcp [Formula: see text] icosahedral [Formula: see text] fcc. PMID:26795034

  19. Electronic structure of disordered Cu-Ag alloys

    International Nuclear Information System (INIS)

    We present a self-consistent-field Korringa-Kohn-Rostoker coherent potential approximation study of the electronic structure of disordered CuxAg1-x alloys for x=0.0, 0.25, 0.50, 0.75 and 1.0. In particular, we focus on the Fermi surface, density of states, and Bloch spectral density, and study how they evolve as a function of x. We find that, Fermi surface dimensions have a non-linear composition dependence. The disorder-induced smearing of the Fermi surface, as expected, is very high along the direction; both the Cu and Ag Fermi surfaces have a neck in this direction. Whenever possible we have compared our results with the available experimental data. (author). 34 refs, 4 figs

  20. Preparation and Photocatalytic Activity of Ag Modified Ti-Doped-Bi2O3 Photocatalyst

    OpenAIRE

    Lilan Zhang; Junfeng Niu; Duo Li; Ding Gao; Jianghong Shi

    2014-01-01

    Ti doped Bi2O3 (TDB) and Ag ion modified Ti doped Bi2O3 (Ag@TDB) photocatalysts were prepared by framework replacement synthesis method with different Ag loadings (0.05, 0.3, 0.75, and 1.0 mol/L AgNO3). The structural properties of the prepared catalysts were studied by scanning electron microscope (SEM), X-ray diffraction (XRD), BET surface area, and UV/Vis diffuse reflectance (DRS). The XRD spectra of the Ti doped Bi2O3 calcined at 650°C showed the diffraction peaks of a mixture of Bi12TiO2...

  1. SYNTESIST AND CHARACTERISATION TiO2-Cu PHOTOCATALYST

    Directory of Open Access Journals (Sweden)

    Kapti Riyani

    2015-11-01

    Full Text Available This study begins with the manufacture of TiO2 -Cu photocatalyst by means of wet impregnation and fotodeposisi, the mole ratio of TiO2: Cu2+ is 100: 0; 99: 1; 98: 2; 97: 3 and 96: 4. Photocatalysts were characterized using SEM, UV-Vis DRS, FTIR and XRD. The results showed has been successfully carried out the synthesis of TiO2-Cu. From SEM characterization shows that the addition of Cu metal will alter the morphology of TiO2 photocatalysts. Based on analysis of UV-Vis DRS, the addition of Cu metal dopant to decrease the energy band gap of TiO2. From XRD analysis appears 2θ value at 29.607 and 48.401 which indicates the formation of monoclinic crystal H2Ti3O7. FTIR analysis results indicate a change in the specific uptake of TiO2 indicating a change in the structure of TiO2

  2. Optical and magnetic properties of Cu-doped 13-atom Ag nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Yi [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xian 710072 (China); Lei, Yimin [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xian 710072 (China); Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, New South Wales 2006 (Australia); Cui, Xiangyuan [Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, New South Wales 2006 (Australia); School of Aerospace Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales 2006 (Australia); Liu, Zongwen, E-mail: fuyichen@nwpu.edu.cn [Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, New South Wales 2006 (Australia); Chen, Fuyi, E-mail: zongwen.liu@sydney.edu.au [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xian 710072 (China)

    2013-07-15

    Highlights: •Cu atom tends to occupy the core position in the Ag–Cu nanoclusters. •Global minimum of Ag{sub 12}Cu{sub 1} cluster is predicted to be cuboctahedral shape. •High symmetry clusters have high magnetic moment. •Icosahedral core–shell Ag{sub 12}Cu{sub 1} cluster has ferromagnetic properties. -- Abstract: The structural, optical and magnetic properties of Ag{sub 13}, Ag{sub 12}Cu{sub 1} and Cu{sub 13} clusters have been investigated using density functional theory calculations. The global minimum of the Ag{sub 12}Cu{sub 1} cluster is predicted to be cuboctahedral (COh) core–shell structure with O{sub h} point group symmetry while the icosahedral (Ih) core–shell isomer has a higher HOMO–LUMO gap and higher magnetic moment. The optical absorption spectrum of the Ih Ag{sub 12}Cu{sub 1} has three absorption peaks at 2.17, 2.41 and 2.65 eV, compared with that the COh Ag{sub 12}Cu{sub 1} has one main absorption peak at 2.51 eV. The characteristics in electronic density of states (DOSs) show that Ih core–shell Ag{sub 12}Cu{sub 1} has ferromagnetic properties like pure Au{sub 13}, Ag{sub 13} nanoclusters. The sizable split between spin up and spin down DOS of d states in the inner Cu atom and sp states in the outer Ag atoms bring in large magnetic moment to Ih Ag{sub 12}Cu{sub 1} cluster.

  3. Electronic conductivity of mechanochemically synthesized nanocrystalline Ag1-CuI system using DC polarization technique

    Indian Academy of Sciences (India)

    D Bharathi Mohan; C S Sunandana

    2006-08-01

    A study of electronic conductivity using the DC polarization technique has been carried out for AgI and Ag1-CuI (where = 0.05, 0.15, 0.25) solid solutions over a range of temperatures from 300 K to 473 K. A diode-like current-voltage characteristics arises from microscopic p-n junctions and an enhanced electronic conductivity of the order of 10-3A is observed for undoped AgI and Cu-doped AgI. Activation energies (a) for electronic conductivity obtained from log (-1 cm-1) vs. 1000/(K-1) were 0.48, 0.6, 0.74 and 1.01 eV for AgI, Ag0.95Cu0.05I, Ag0.85Cu0.15I and Ag0.75Cu0.25I solid solutions respectively. The near-twofold increase in activation energy (1.01 eV) observed upon 25% Cu doping is due to the substantial concentration of current carriers/holes injected by Cu while replacing Ag+ in AgI.

  4. Untersuchung und Charakterisierung des Phasengebietes M-Q-X (M = Ag, Cu; Q = Chalkogen; X = Halogen)

    OpenAIRE

    Giller, Malte

    2015-01-01

    Diese Dissertation beschreibt die Synthese und Charakterisierung von neuen Verbindungen, im Phasengebiet Cu-Te-Br und Cu-Te-S, sowie der festen Lösung von Cu10Te4Cl3 und Ag10Te4Br3. Hierbei wurden drei neue Phasen, Cu4.8(1)Te3Br, Cu5.4(1)Te3Br und Cu6Te3S isoliert und als kupfergefüllte Varianten des Cr3Si-Strukturtyps charakterisiert.

  5. Preparation of CaCu3Ti4O12 using a wet chemical method

    International Nuclear Information System (INIS)

    CaCu3Ti4O12 was synthesized starting from a solution of TiO2 to which Ca and Cu nitrates were added. Due to the differences in the solubilities of the Ca, Cu and Ti, initial variations from ideal stoichiometry and a high solution pH was necessary to obtain stoichiometric CaCu3Ti4O12 precipitates. As precipitated samples were amorphous with CuO phases observed after drying of the precipitates at 300 degree C. CaCu3Ti4O12 phases was observed after heat treatment at 1000 degree C. XRD studies show the presence of CuO and TiO2 in addition to the CaCu3Ti4O12 for non-stoichiometric samples. Observations under the SEM show the presence of Cu rich and Ti rich phases in addition to the CaCu3Ti4O12. (Author)

  6. Facile preparation of Ag-Cu bifunctional electrocatalysts for zinc-air batteries

    International Nuclear Information System (INIS)

    Highlights: • Ag-Cu dendrites are observed for the first time to exhibit high catalytic activity for oxygen reduction reaction. • Ag-Cu dendrites are directly synthesized through galvanic displacement on the current collector layer made of Ni foams. • A bifunctional air cathode is fabricated using Ag-Cu dendrites as a carbon-free, binder-free catalyst layer. • Both the primary and rechargeable zinc–air batteries fabricated by Ag-Cu catalysts exhibit excellent performance. - ABSTRACT: An inexpensive, facile galvanic displacement reaction for the direct growth of silver–copper (Ag-Cu) catalysts on nickel foams is developed for the first time. The resulting Ag-Cu catalysts exhibit dendritic morphologies. Ag and Cu atoms are in their metallic state while the presence of CuO and Cu2O are limited on the surface of catalyst. The catalysts demonstrate high catalytic activity for oxygen reduction reaction (ORR) in alkaline solution, as evaluated by both linear scanning voltammetry and rotating disk electrode polarization measurements. The ORR catalysed by Ag-Cu catalyst in alkaline solution proceeds through a four-electron pathway. An air cathode is fabricated using Ag-Cu catalyst as a carbon-free, binder-free catalyst layer. Using this Ag-Cu catalyst based air cathode, both the primary and rechargeable zinc-air batteries show excellent battery performance. The specific capacity of the primary zinc-air battery is 572 mAh g−1. Especially, the rechargeable zinc-air battery shows high round-trip efficiency, appealing stability at a long charge-discharge cycle period

  7. Direct in situ activation of Ag0 nanoparticles in synthesis of Ag/TiO2 and its photoactivity

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Ag0 loaded on TiO2 was prepared by a direct in situ electrochemical method. • 5 wt% Ag–TiO2 demonstrated the best photocatalytic degradation of 2-CP. • Isomorphous substitution of Ag with Ti occurred to form Ti−O−Ag bonds. • Ag0 and oxygen vacancies trapped electrons to enhance e–H+ separation. • Substitution of Ag in the TiO2 structure decreased the number of oxygen vacancies. - Abstract: Metallic Ag nanoparticles (Ag0) were successfully activated using a direct in situ electrochemical method before being supported on TiO2. Catalytic testing showed that 5 wt% Ag–TiO2 gave the highest photodegradation (94%) of 50 mg L−1 2-chlorophenol (2-CP) at pH 5 using 0.375 g L−1 catalyst within 6 h, while under similar conditions, 1 wt% and 10 wt% Ag–TiO2 only gave 75% and 78% degradation, respectively. Characterization results illustrated that the photoactivity was affected by the amount of Ag0 and oxygen vacancies which act as an electrons trap to enhance the electron–hole separation. While, the Ag−O−Ti bonds formation reduced the photoactivity. The degradation followed a pseudo-first order Langmuir–Hinshelwood model where adsorption was the controlling step. Study on the effect of scavengers showed that the hole (H+) and hydroxyl radical (OH·) play important roles in the photodegradation. The regenerated photocatalyst was still stable after five cycling runs

  8. Slow positron studies on single crystals of Ag(100), Ag(111) and Cu(111)

    International Nuclear Information System (INIS)

    Monoenergetic positrons were employed to examine positronium formation as a function of sample temperature (300 to 1200 K) and incident energy (0 to 5 keV) on Ag(100), Ag(111) and Cu(111) surfaces with submonolayer contamination. In these metals at the higher temperatures, positronium formation becomes the dominant process. A one-dimensional diffusion model is fit to the data as a function of incident energy. Th positronium fraction is found to be an activated process and is identified as detrapping from a surface state and an estimate of the depth of this trap is extracted. The diffusion length is found to be temperature independent before the onset of vacancy trapping. At the higher temperatures vacancy trapping is observed by the decrease in the positron diffusion length at the higher incident voltages. A vacancy formation energy is extracted from the data and is generally lower than the accepted bulk values. 18 references

  9. Synthesis and characterization of nano-CuO and CuO/TiO2 photocatalysts

    International Nuclear Information System (INIS)

    CuO nanocrystals were prepared by thermal decomposition of Cu-oxalate at 400 °C; then CuO/TiO2 core/shell nanocrystals were formed via the hydrolysis of titanium isopropoxide (TIP) on the surface of CuO nanocrystals. The characteristics of the synthesized nanocrystals were systematically studied using appropriate techniques, namely the morphology by using scanning electron microscopy (SEM), and the crystalline structure by x-ray powder diffraction (XRD) and Raman spectroscopy. The structure, shape and size of the CuO and CuO/TiO2 nanocrystals could be tuned by changing various technological parameters: (i) the reaction/growth time (from several minutes to several hours), (ii) reaction temperature (from room temperature to 90 °C) and (iii) the molar ratios of the precursors. The results showed that the reaction temperature and the molar ratio of the precursors play important roles in controlling the morphology and size of both CuO and CuO/TiO2 nanocrystals. With increasing reaction temperature, nano-CuO evolved from spherical shaped nanoparticles to microspheres. By shelling the large-bandgap TiO2 layers on CuO nanocrystals, the core/shell structure is formed and the narrow-bandgap nano-CuO core is expected to be resistant to photocorrosion. (paper)

  10. Fabrication, characterization and photocatalytic properties of Ag nanoparticles modified TiO2 NTs

    International Nuclear Information System (INIS)

    Graphical abstract: The TiO2 NTs were first treated with bi-functional mercaptoacetic acid linkers (HOOC–R–S). The –OH group on the surface of TiO2 NT provides a strong affinity with the carboxylate group in the linker molecules. The thiol functional group in the linker molecules facilitates the binding with Ag from AgNO3 solution. After Ag+ ions were reduced by NaBH4, Ag nanoparticles formed by nucleation and growth. Highlights: ► Ag nanoparticles with an average diameter of 9.2 nm were filled in the TiO2 nanotubes by a successive ionic layer adsorption and reaction (SILAR) technique. ► Bi-functional mercaptoacetic acid linkers were used to bind TiO2 nanotubes with Ag nanoparticles. ► Ag nanoparticles modification of TiO2 NTs largely enhanced the photocatalytic degradation of methyl orange under ultraviolet light irradiation. - Abstract: Ordered anatase TiO2 nanotubes (TiO2 NTs) on Ti substrate were synthesized by electrochemical anodization and subsequently vapor-thermal treatment. Ag nanoparticles were decorated on TiO2 NTs by successive ionic layer adsorption and reaction (SILAR) technique. Raman spectroscopy, X-ray absorption near edge spectroscopy (XANES), X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used for the characterization of surface morphology, phase composition, and microstructure of the original TiO2 NTs, the vapor-thermally treated TiO2 NTs and the Ag nanoparticles decorated TiO2 NTs. The results indicate that vapor-thermal treatment favors to the transformation of amorphous TiO2 into anatase phase. Increasing the SILAR cycle times favors to increase the loaded amounts of Ag nanoparticles in TiO2 NTs. Ag nanoparticles are uniformly distributed in the TiO2 NTs, and the SILAR process does not damage the ordered tubular structure. A possible formation mechanism of Ag/TiO2 NTs has also been proposed. The photocatalytic results showed

  11. AgCuVO{sub 4}: A quasi one-dimensional S=1/2 compound

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, Angela; Taetz, Timo [Universitaet zu Koeln (Germany). Institut fuer Anorganische Chemie; Schmitt, Miriam; Rosner, Helge [Max Planck Institute for Chemical Physics of Solids, Dresden (Germany)

    2009-07-01

    Recently, we have been able to synthesize the new copper-orthovanadate AgCuVO{sub 4}. The crystal structure was determined by single crystal x-ray diffraction. AgCuVO{sub 4} comprises Cu{sup 2+} ions coordinated by oxygen in a square-planar fashion, similar to LiCuVO{sub 4}, which has been identified as a multiferroic material recently. Whereas in LiCuVO{sub 4} the square-planar [CuO{sub 4}] units are connected via edges to form chains along the crystallographic b axis, the [CuO{sub 4}] units in AgCuVO{sub 4} are connected via corners resulting in Cu-O-Cu chains along the b-axis. The static magnetic susceptibility of AgCuVO{sub 4} can be described quite well within a Bonner-Fisher spin-chain scenario. In order to gain microscopic insight into the the electronic structure and the magnetic exchange interactions of AgCuVO{sub 4}, we performed LDA band structure calculations. To take the strong Coulomb repulsion at the Cu site into account, we mapped the LDA results onto a tight binding model and subsequently onto a Heisenberg model. In agreement with the experimental data, we find pronounced one-dimensional magnetic exchange along the b axis with small inter-chain couplings.

  12. Study on synthesis of ultrafine Cu-Ag core-shell powders with high electrical conductivity

    Science.gov (United States)

    Peng, Yu-hsien; Yang, Chih-hao; Chen, Kuan-ting; Popuri, Srinivasa R.; Lee, Ching-Hwa; Tang, Bo-Shin

    2012-12-01

    Cu-Ag composite powders with high electrical conductivity were synthesized by electroless plating of silver sulfate, copper powders with eco-friendly sodium citrate as reducing agent, dispersant and chelating agent in an aqueous system. The influences of sodium citrate/Ag ratio on Ag coatings of Cu powders were investigated. Ag was formed a dense coating on the surface of Cu powders at a molar ratio of sodium citrate/Ag = 0.07/1. SEM showed an uniformity of Ag coatings on Cu powders. SEM-EDX also revealed that Cu cores were covered by Ag shells on the whole. The surface composition analysis by XPS indicated that without Cu or Ag atoms in the surface were oxidized. The resistivity measurements of Cu-Ag paste shows that they have closer resistivity as the pure silver paste's after 250 °C for 30 min heat-treatment (2.55 × 10-4 Ω cm) and 350 °C for 30 min heat-treatment (1.425 × 10-4 Ω cm).

  13. High-pressure x-ray diffraction of icosahedral Zr-Al-Ni-Cu-Ag quasicrystals

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Saksl, Karel; Rasmussen, Helge Kildahl;

    2001-01-01

    The effect of pressure on the structural stability of icosahedral Zr-Al-Ni-Cu-Ag quasicrystals forming from a Zr65Al7.5Ni10Cu7.5Ag10 metallic glass with a supercooled liquid region of 44 K has been investigated by in situ high-pressure angle-dispersive x-ray powder diffraction at ambient temperat...

  14. Biological properties of nanostructured Ti incorporated with Ca, P and Ag by electrochemical method

    Energy Technology Data Exchange (ETDEWEB)

    Li, Baoe; Hao, Jingzu; Min, Yang [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Xin, Shigang [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Guo, Litong [School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou 221116 (China); He, Fei [National Key Laboratory of C1 Chemical Industry, Tianjin University, Tianjin 300072 (China); Liang, Chunyong; Wang, Hongshui [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Li, Haipeng, E-mail: lhpcx@163.com [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China)

    2015-06-01

    TiO{sub 2} nanotube arrays were synthesized on Ti surface by anodic oxidation. The elements of Ca and P were simultaneously incorporated during nanotubes growth in SBF electrolyte, and then Ag was introduced to nanotube arrays by cathodic deposition, which endowed the good osseointegration and antibacterial property of Ti. The bioactivity of the Ti surface was evaluated by simulated body fluid soaking test. The biocompatibility was investigated by in vitro cell culture test. And the antibacterial effect against Staphylococcus aureus was examined by the bacterial counting method. The results showed that the incorporation of Ca, P and Ag elements had no significant influence on the formation of nanotube arrays on Ti surface during electrochemical treatment. Compared to the polished or nanotubular Ti surface, TiO{sub 2} nanotube arrays incorporated with Ca, P and Ag increased the formation of bone-like apatite in simulated body fluid, enhanced cell adhesion and proliferation, and inhibited the bacterial growth. Based on these results, it can be concluded that the nanostructured Ti incorporated with Ca, P and Ag by electrochemical method has promising applications as implant material. - Highlights: • Nanotube arrays were prepared on Ti surface by anodic oxidation. • Ca, P and Ag were incorporated to nanotube arrays by electrochemical method. • Ca, P and Ag endowed Ti with good osseointegration and antibacterial property. • The beneficial effect of electrochemical treatment on Ti implant was demonstrated.

  15. Biological properties of nanostructured Ti incorporated with Ca, P and Ag by electrochemical method

    International Nuclear Information System (INIS)

    TiO2 nanotube arrays were synthesized on Ti surface by anodic oxidation. The elements of Ca and P were simultaneously incorporated during nanotubes growth in SBF electrolyte, and then Ag was introduced to nanotube arrays by cathodic deposition, which endowed the good osseointegration and antibacterial property of Ti. The bioactivity of the Ti surface was evaluated by simulated body fluid soaking test. The biocompatibility was investigated by in vitro cell culture test. And the antibacterial effect against Staphylococcus aureus was examined by the bacterial counting method. The results showed that the incorporation of Ca, P and Ag elements had no significant influence on the formation of nanotube arrays on Ti surface during electrochemical treatment. Compared to the polished or nanotubular Ti surface, TiO2 nanotube arrays incorporated with Ca, P and Ag increased the formation of bone-like apatite in simulated body fluid, enhanced cell adhesion and proliferation, and inhibited the bacterial growth. Based on these results, it can be concluded that the nanostructured Ti incorporated with Ca, P and Ag by electrochemical method has promising applications as implant material. - Highlights: • Nanotube arrays were prepared on Ti surface by anodic oxidation. • Ca, P and Ag were incorporated to nanotube arrays by electrochemical method. • Ca, P and Ag endowed Ti with good osseointegration and antibacterial property. • The beneficial effect of electrochemical treatment on Ti implant was demonstrated

  16. Electromigration performance improvement of Al-Si-Cu/TiN/Ti/n+Si contact

    Science.gov (United States)

    Shi, Gang; Sun, Zhen; Xu, Geng-Fu; Min, Yun-Hao; Luo, Jun-Yi; Lu, Yong; Li, Bing-Zong; Qu, Xin-Ping; Qian, Gang; Doan, My T.; Lee, Edmund

    1998-02-01

    In this study, two different processes, with and without rapid thermal annealing (RTA), have been compared for the Al-Si- Cu/TiN/Ti multilayer contact on n+ diffusions. A series of wafer level reliability (WLR) measurement performed on a test structure with two 1.08 X 1.08 micrometer2 contacts on n+ diffusion. The results show that RTA can increase contact electromigration (EM) lifetime dramatically. The XRD, AES and TEM analysis indicate that this improvement is attributed to oxygen stuffing in TiN, phase change of TiN and TiSi2 formation at the interface of Ti and Si.

  17. Single-molecule conductance with nitrile and amino contacts with Ag or Cu electrodes

    International Nuclear Information System (INIS)

    The single-molecule conductance of 1,4-dicyanobenzene (DCB), 1,4-benzenediamine (BDA) and 4,4'-biphenyldicarbonitrile (BPDC) with Ag and/or Cu electrodes is measured by electrochemical jump-to-contact STM-break junction. All single-molecule junctions present three sets of conductance values revealing different contact geometries. We observe that the single-molecule conductance of Ag-BDA-Ag junction is larger that of Ag-DCB-Ag junction, and DCB with Ag contacts are more conductive than that with Cu ones. This is related to a different electronic coupling between the molecules and the electrodes. Tunneling decay constants of 1.70 and 1.68 per phenyl group were found for Ag and Cu electrodes, respectively. The present study therefore shows that nitrile and amino groups can also be used as effective anchors for other metals than gold

  18. Study on synthesis of ultrafine Cu-Ag core-shell powders with high electrical conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Peng Yuhsien [Department of Environmental Engineering, Dayeh University, 168 University Rd., Dacun, Changhua 515, Taiwan (China); Department of Research and Development, Oriental Happy Enterprise Co., No. 27, Xin' ai Rd., South Dist., Tainan 702, Taiwan (China); Center for General Education, Kun Shan University, No. 949, Dawan Rd., Yongkang Dist., Tainan 710, Taiwan (China); Yang Chihhao [Department of Research and Development, Oriental Happy Enterprise Co., No. 27, Xin' ai Rd., South Dist., Tainan 702, Taiwan (China); Chen Kuanting, E-mail: pengyuhsien@hotmail.com [Department of Resources Engineering, National Cheng Kung University, No.1, Da-Hsueh Road, Tainan 701, Taiwan (China); Popuri, Srinivasa R. [Department of Biological and Chemical Sciences, The University of the West Indies, Cave Hill Campus 11000 (Barbados); Lee, Ching-Hwa [Department of Environmental Engineering, Dayeh University, 168 University Rd., Dacun, Changhua 515, Taiwan (China); Tang, Bo-Shin [Department of Research and Development, Oriental Happy Enterprise Co., No. 27, Xin' ai Rd., South Dist., Tainan 702, Taiwan (China)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer This synthesis method is relatively facile, novel and eco-friendly. Black-Right-Pointing-Pointer Toxic agents were not used for chelating agent, reductant or dispersant in our method. Black-Right-Pointing-Pointer The reaction can under room temperature for energy saving purpose. Black-Right-Pointing-Pointer Cu-Ag core-shell powders with homogeneous cover-silver layer. Black-Right-Pointing-Pointer The resistivity of Cu-Ag core-shell powders has the same value as the pure silver. - Abstract: Cu-Ag composite powders with high electrical conductivity were synthesized by electroless plating of silver sulfate, copper powders with eco-friendly sodium citrate as reducing agent, dispersant and chelating agent in an aqueous system. The influences of sodium citrate/Ag ratio on Ag coatings of Cu powders were investigated. Ag was formed a dense coating on the surface of Cu powders at a molar ratio of sodium citrate/Ag = 0.07/1. SEM showed an uniformity of Ag coatings on Cu powders. SEM-EDX also revealed that Cu cores were covered by Ag shells on the whole. The surface composition analysis by XPS indicated that without Cu or Ag atoms in the surface were oxidized. The resistivity measurements of Cu-Ag paste shows that they have closer resistivity as the pure silver paste's after 250 Degree-Sign C for 30 min heat-treatment (2.55 Multiplication-Sign 10{sup -4} {Omega} cm) and 350 Degree-Sign C for 30 min heat-treatment (1.425 Multiplication-Sign 10{sup -4} {Omega} cm).

  19. Photocatalytic performances and activities of Ag-doped CuFe2O4 nanoparticles

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • CuFe2O4 nanocrystals were synthesized by a co-precipitation method. • Ag/CuFe2O4 catalyst was prepared by the wetness impregnation strategy. • The structural properties of Ag/CuFe2O4 were investigated by XRD, TEM, DRS, and XPS techniques. • Ag/CuFe2O4 has higher photocatalytic activity. - Abstract: In this work, CuFe2O4 nanoparticles were synthesized by a chemical co-precipitation route. The Ag/CuFe2O4 catalyst was prepared based on the CuFe2O4 nanoparticles by the incipient wetness impregnation strategy, which showed excellent photoelectric property and catalytic activity. The structural properties of these samples were systematically investigated by X-ray powder diffraction (XRD), transmission electronic microscopy (TEM), UV–vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) techniques. The photo-induced charge separation in the samples was demonstrated by surface photovoltage (SPV) measurement. The photocatalytic degradation of 4-CP by the Ag/CuFe2O4 and CuFe2O4 samples were comparatively studied under xenon lamp irradiation. The results indicate that the Ag/CuFe2O4 sample exhibited the higher efficiency for the degradation of 4-CP

  20. The study on interfacial bonding strength of Ag-Ni, Ag-Cu in cold pressure welding

    Institute of Scientific and Technical Information of China (English)

    李云涛; 杜则裕; 陈丽萍

    2003-01-01

    The area of combination actually is a kind of interfacial phenomena that exist on the surface or thin film. The properties of interface have important effect on the whole welded joint, even decide directly the interfacial bonding strength. The bonding strength of metals in cold pressure welding such as Ag-Ni (they are hardly mutual soluble) and Ag-Cu(they are limited soluble) are discussed in this paper. The results of the tensile test suggest that two kinds of welded joints have enough strength to satisfy with the demand for being used. Moreover, thermodynamics, crystal logy, physics and metal electronic microscopic analysis etc are adopted to further calculate the bonding strength. The results of test and theoretical analyses prove that Ag-Ni, Ag-Cu, especially, for Ag-Ni can form strong welded joint which is higher than that of the relative soft base metals in cold pressure welding.

  1. Surface alloying of Cu with Ti by double glow discharge process

    Institute of Scientific and Technical Information of China (English)

    袁庆龙; 池成忠; 苏永安; 徐重; 唐宾

    2004-01-01

    The surface of pure copper alloyed with Ti using double glow discharge process was investigated. The morphology, structure and forming mechanism of the Cu-Ti alloying layer were analyzed. The microhardness and wear resistance of the Cu-Ti alloying layer were measured, and compared with those of pure copper. The results indicate that the surface of copper activated by Ar and Ti ions bombardment is favorable to absorption and diffusion of Ti element. In current experimental temperature, as the Ti content increases, the liquid phase occurs between the deposited layer and diffused layer, which makes the Ti ions and atoms easy to dissolve and the thickness of Cu-Ti alloying layer increase rapidly. After cooling, the structure of the alloying layer is composed of CuTi, Cu4 Ti and Cu(Ti) solid solution. The solid solution strengthening and precipitation strengthening effects of Ti result in high surface hardness and wear resistance.

  2. Ag-bridged Ag2O nanowire network/TiO2 nanotube array p–n heterojunction as a highly efficient and stable visible light photocatalyst

    International Nuclear Information System (INIS)

    Graphical abstract: A unique Ag-bridged Ag2O nanowire network/TiO2 nanotube array p–n heterojunction was fabricated by simple electrochemical method. The heterostructures exhibit high photocatalytic activity and excellent recycling performance. - Highlights: • Ag-bridged Ag2O nanowire network self-stability structure. • Ag2O nanowire network/TiO2 nanotube p–n heterojunction. • High visible light photocatalytic activity. • Highly stable recycling performance. - Abstract: A unique Ag-bridged Ag2O nanowire network/TiO2 nanotube array p–n heterojunction (Ag–Ag2O/TiO2 NT) was fabricated by simple electrochemical method. Ag nanoparticles were firstly electrochemically deposited onto the surface of TiO2 NT and then were partly oxidized to Ag2O nanowires while the rest of Ag mother nanoparticles were located at the junctions of Ag2O nanowire network. The Ag–Ag2O/TiO2 NT heterostructure exhibited strong visible-light response, effective separation of photogenerated carriers, and high adsorption capacity. The integration of Ag–Ag2O self-stability structure and p–n heterojunction permitted high and stable photocatalytic activity of Ag–Ag2O/TiO2 NT heterostructure photocatalyst. Under 140-min visible light irradiation, the photocatalytic removal efficiency of both dye acid orange 7 (AO7) and industrial chemical p-nitrophenol (PNP) over Ag–Ag2O/TiO2 NT reached nearly 100% much higher than 17% for AO7 or 13% for PNP over bare TiO2 NT. After 5 successive cycles under 600-min simulated solar light irradiation, Ag–Ag2O/TiO2 NT remained highly stable photocatalytic activity

  3. Experimental study on the phase equilibria of the Ag-Ti system

    Energy Technology Data Exchange (ETDEWEB)

    Fu Xiaoliang [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Li Changrong [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)]. E-mail: crli@mater.ustb.edu.cn; Wang Fuming [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Li Mei [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhang Weijing [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

    2005-11-05

    The Ag-Ti diffusion couples were prepared by small pure silver plates closely packed in pure titanium powder, sealed in quartz tube, and annealed at 750 deg. C, 980 deg. C, 1100 deg. C and 1200 deg. C, respectively. The phase equilibrium relationship and the conjugate phase compositions in the Ag-Ti system were determined by means of the metallographic microscope and the electron probe microanalysis. Partial liquidus and solidus for the two-phase equilibrium, liquid + ({beta}Ti), were obtained. The narrow solution range for the intermediate phase (TiAg) was determined.

  4. Microstructure evolution of Ti-Si-C-Ag nanocomposite coatings deposited by DC magnetron sputtering

    International Nuclear Information System (INIS)

    Nanocomposite coatings consisting of Ag and TiCx (x < 1) crystallites in a matrix of amorphous SiC were deposited by high-rate magnetron sputtering from Ti-Si-C-Ag compound targets. Different target compositions were used to achieve coatings with a Si content of ∼13 at.%, while varying the C/Ti ratio and Ag content. Electron microscopy, helium ion microscopy, X-ray photoelectron spectroscopy and X-ray diffraction were employed to trace Ag segregation during deposition and possible decomposition of amorphous SiC. Eutectic interaction between Ag and Si is observed, and the Ag forms threading grains which coarsen with increased coating thickness. The coatings can be tailored for conductivity horizontally or vertically by controlling the shape and distribution of the Ag precipitates. Coatings were fabricated with hardness in the range 10-18 GPa and resistivity in the range 77-142 μΩ cm.

  5. The behavior and effect of CuO in Ag/SnO{sub 2} materials

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jun, E-mail: Wangjun1983@stu.xjtu.edu.cn [MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi’an Jiaotong University, Xi’an 710049 (China); Liu, Wei, E-mail: 810779396@qq.com [MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi’an Jiaotong University, Xi’an 710049 (China); Li, Dongmei, E-mail: 946346365@qq.con [MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi’an Jiaotong University, Xi’an 710049 (China); Wang, Yaping, E-mail: ypwang@mail.xjtu.edu.cn [MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi’an Jiaotong University, Xi’an 710049 (China); State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049 (China)

    2014-03-05

    Highlights: • The crystallized monoclinic CuO in CuO-doped SnO{sub 2} nanoparticles had formed. • The crystallized monoclinic CuO distributed on the surface of SnO{sub 2} nanoparticles. • Ag/SnO{sub 2} materials adding CuO exhibited denser microstructure and better hardness. • Ag/SnO{sub 2} materials adding CuO exhibited better arc erosion resistance. • The addition of CuO can obviously inhibited the spattering loss of molten droplet. -- Abstract: In this paper, the behavior of CuO in CuO-doped SnO{sub 2} nanoparticles was investigated; the effect of the addition of CuO on physical properties and arc erosion behavior of Ag/SnO{sub 2} materials were examined. The CuO-doped SnO{sub 2} nanoparticles were structurally characterized by X-ray diffraction (XRD) and High-resolution Transmission Electron Microscope (HR-TEM). The surface morphology of arc eroded Ag/SnO{sub 2} materials was characterized by Scanning Electron Microscope (SEM). The results indicated that the crystallized monoclinic CuO in CuO-doped SnO{sub 2} nanoparticles has formed and distributed on the surface of SnO{sub 2} nanoparticles. It was found that Ag/SnO{sub 2} materials adding CuO exhibited denser microstructure and better hardness as well as better arc erosion resistance compared with Ag/SnO{sub 2} materials. The arc erosion results and theoretical analysis indicated that the addition of CuO in Ag/SnO{sub 2} materials can obviously inhibited the spattering loss of molten droplets.

  6. The behavior and effect of CuO in Ag/SnO2 materials

    International Nuclear Information System (INIS)

    Highlights: • The crystallized monoclinic CuO in CuO-doped SnO2 nanoparticles had formed. • The crystallized monoclinic CuO distributed on the surface of SnO2 nanoparticles. • Ag/SnO2 materials adding CuO exhibited denser microstructure and better hardness. • Ag/SnO2 materials adding CuO exhibited better arc erosion resistance. • The addition of CuO can obviously inhibited the spattering loss of molten droplet. -- Abstract: In this paper, the behavior of CuO in CuO-doped SnO2 nanoparticles was investigated; the effect of the addition of CuO on physical properties and arc erosion behavior of Ag/SnO2 materials were examined. The CuO-doped SnO2 nanoparticles were structurally characterized by X-ray diffraction (XRD) and High-resolution Transmission Electron Microscope (HR-TEM). The surface morphology of arc eroded Ag/SnO2 materials was characterized by Scanning Electron Microscope (SEM). The results indicated that the crystallized monoclinic CuO in CuO-doped SnO2 nanoparticles has formed and distributed on the surface of SnO2 nanoparticles. It was found that Ag/SnO2 materials adding CuO exhibited denser microstructure and better hardness as well as better arc erosion resistance compared with Ag/SnO2 materials. The arc erosion results and theoretical analysis indicated that the addition of CuO in Ag/SnO2 materials can obviously inhibited the spattering loss of molten droplets

  7. (RE)BaCuO/Ag composites: fundamentals of processing, microstructure and control of properties

    International Nuclear Information System (INIS)

    We have investigated the phase equilibria in (RE)BaCuO-Ag systems, the influence of Ag on the processing of (RE)BaCuO/Ag composites and the resulting properties. YBCO/Ag composites have been grown by the modified melt crystallization process with YBa2Cu3O7, Y2O3, Pt and Ag2O in the precursor. The improved strength of the YBCO/Ag composites compared with the conventional YBCO bulk material permitted us to magnetize these materials to achieve trapped fields up to 16 T (at 24 K) in the gap of a mini-magnet. The investigation of the microstructure revealed a remarkable increase of the spacing between micro-cracks especially of those perpendicular to a-b planes when 12 wt% Ag was added. In the case of SmBaCuO/Ag composites Ag has a strong influence on processing and causes interactions between RE123 seeds and the sample. We report on the growth of single-grain SmBaCuO/Ag composites in air and we discuss the influence of post-annealing on increasing Tc and jc. (author)

  8. Fabrication and photoelectrochemical study of vertically oriented TiO2/Ag/SiNWs arrays

    International Nuclear Information System (INIS)

    Highlights: • TiO2/Ag/SiNWs with porous structure and high surface area were synthesized. • The successful incorporating of Ag significantly enhanced the photocatalyst activity. • The novel structure improves the separation of photo-induced charge carriers in the structures. • This research provides a meaning way in light-harvesting devices. - Abstract: Ordered channeled and porous TiO2 and Ag modified silicon nanowires (TiO2/Ag/SiNWs) heterostructured nanocrystals arrays are synthesized by a two-step method based on an electrochemical etching procedure and a sol–gel process. The morphology and photoelectrochemical properties of the TiO2/Ag/SiNWs are studied. The TiO2/Ag/SiNWs photocatalysts possess ordered channels and a porous structure with large specific surface area. UV–visible diffuse reflectance spectroscopy and ultraviolet Raman scattering demonstrate that the incorporated Ag significantly enhances light absorption by the TiO2/SiNWs in the visible spectral range and improves the separation of photo-induced charge carriers in the TiO2/SiNWs. The photoelectrochemical properties of the TiO2/Ag/SiNWs are investigated by monitoring the degradation of pnitrophenol (PNP) and Ag enhances PNP photodegradation under UV–vis irradiation due to the Ag–TiO2 heterojunctions and surface texture. The photoelectrochemical properties of TiO2/Ag/SiNWs have promising applications in photoelectrochemical solar cells and other light-harvesting devices

  9. Cellular Energy Allocation to Assess the Impact of Nanomaterials on Soil Invertebrates (Enchytraeids: The Effect of Cu and Ag

    Directory of Open Access Journals (Sweden)

    Susana I. L. Gomes

    2015-06-01

    Full Text Available The effects of several copper (Cu and silver (Ag nanomaterials were assessed using the cellular energy allocation (CEA, a methodology used to evaluate the energetic status and which relates with organisms’ overall condition and response to toxic stress. Enchytraeus crypticus (Oligochatea, was exposed to the reproduction effect concentrations EC20/50 of several Cu and Ag materials (CuNO3, Cu-Field, Cu-Nwires and Cu-NPs; AgNO3, Ag NM300K, Ag-NPs Non-coated and Ag-NPs PVP-coated for 7 days (0-3-7d. The parameters measured were the total energy reserves available (protein, carbohydrate and lipid budgets and the energy consumption (Ec integrated to obtain the CEA. Results showed that these parameters allowed a clear discrimination between Cu and Ag, but less clearly within each of the various materials. For Cu there was an increase in Ec and protein budget, while for Ag a decrease was observed. The results corroborate known mechanisms, e.g., with Cu causing an increase in metabolic rate whereas Ag induces mitochondrial damage. The various Cu forms seem to activate different mechanisms with size and shape (e.g., Cu-NPs versus Cu-Nwires, causing clearly different effects. For Ag, results are in line with a slower oxidation rate of Ag-NMs in comparison with Ag-salt and hence delayed effects.

  10. Alleviation of process-induced cracking of the antireflection TiN coating (ARC-TiN) in Al-Cu and Al-Cu-Si films

    CERN Document Server

    Peng, Y C; Yang, Y R; Hsieh, W Y; Hsieh, Y F

    1999-01-01

    The alleviation of cracking of the TiN-ARC layer on Al-Cu and Al-Cu-Si films after the development process has been achieved. For the TiN-ARC/Al-Cu system, the stress-induced defects decreased with increasing TiN-ARC layer thickness. In contrast, for the TiN-ARC/Al-Cu-Si system, Si nodules formed during cooling, thereby inducing poor coverage with high aspect-ratio holes. As a result, the photoresist developer penetrated through the films. Chemical vapor deposition of TiN-ARC or predeposition of a Ti Interposing layer was used to eliminate the formation of Si nodules.

  11. Alleviation of process-induced cracking of the antireflection TiN coating (ARC-TiN) in Al-Cu and Al-Cu-Si films

    International Nuclear Information System (INIS)

    The alleviation of cracking of the TiN-ARC layer on Al-Cu and Al-Cu-Si films after the development process has been achieved. For the TiN-ARC/Al-Cu system, the stress-induced defects decreased with increasing TiN-ARC layer thickness. In contrast, for the TiN-ARC/Al-Cu-Si system, Si nodules formed during cooling, thereby inducing poor coverage with high aspect-ratio holes. As a result, the photoresist developer penetrated through the films. Chemical vapor deposition of TiN-ARC or predeposition of a Ti Interposing layer was used to eliminate the formation of Si nodules

  12. Characterization and mechanical properties investigation of TiN-Ag films onto Ti-6Al-4V

    Science.gov (United States)

    Du, Dongxing; Liu, Daoxin; Zhang, Xiaohua; Tang, Jingang; Xiang, Dinggen

    2016-03-01

    To investigate their effect on fretting fatigue (FF) resistance of a Ti-6Al-4V alloy, hard solid lubricating composite films of TiN with varying silver contents (TiN-Ag) were deposited on a Ti-6Al-4V alloy using ion-assisted magnetron sputtering. The surface morphology and structure were analyzed by atomic force microscopy, X-ray diffractometry, X-ray photoelectron spectroscopy, and transmission electron microscopy. The hardness, bonding strength, and toughness of films were tested using a micro-hardness tester, scratch tester, and a repeated press-press test system that was manufactured in-house, respectively. The FF resistance of TiN-Ag composite films was studied using self-developed devices. The results show that the FF resistance of a titanium alloy can be improved by TiN-Ag composite films, which were fabricated using hard TiN coating doped with soft Ag. The FF life of Ag0.5, Ag2, Ag5, Ag10 and Ag20 composite films is 2.41, 3.18, 3.20, 2.94 and 2.87 times as great as that of the titanium alloy, respectively. This is because the composite films have the better toughness, friction lubrication, and high bonding strength. When the atomic fraction of Ag changes from 2% to 5%, the FF resistance of the composite films shows the best performance. This is attributed to the surface integrity of the composite film is sufficiently fine to prevent the initiation and early propagation of FF cracks.

  13. Synthesis and Characterization of Electrospun Nanocomposite TiO Nanofibers with Ag Nanoparticles for Photocatalysis Applications

    Directory of Open Access Journals (Sweden)

    Srujan Mishra

    2012-01-01

    Full Text Available Polycrystalline mixed-phase TiO2 nanofibers embedded with 2.0% w/v Ag nanoparticles was prepared by the electrospinning technique. Calcination of dry Ag nanoparticles-titanium (IV isopropoxide/PVP electrospun nanofiber mats in air at 510∘C for 24 h yielded polycrystalline TiO2/Ag nanofibers. The morphology and distribution of silver nanoparticles were observed by transmission electron microscopy (TEM, scanning TEM (STEM, and high-angle annular dark-field (HAADF imaging. Mixed-phase anatase and rutile TiO2 nanofibers were produced with Ag nanoparticles. High-resolution TEM lattice-fringe measurements showed good agreement with Ag (111, anatase (101, and rutile (110 phases. The photocatalytic activity of TiO2/Ag nanofibers was compared to the photocatalytic activity of pure TiO2 nanofibers by studying the photodegradation of methyl red dye under UV light irradiation, in a photoreactor. UV-visible absorbance spectra showed that the rate of decay of the dye in case of photodegradation by TiO2/Ag nanofibers was 10.3 times higher than that by pure TiO2 nanofibers. The retaining of the fiber morphology along with the increased surface area due to the addition of Ag nanoparticles can be believed to enhance the photocatalytic oxidation of methyl red dye.

  14. Spectroscopic ellipsometry analysis of multilayered TiO{sub 2}-Ag thin films for photochromic application

    Energy Technology Data Exchange (ETDEWEB)

    Miao, L. [Materials R and D Laboratory, Japan Fine Ceramics Centre, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587 (Japan); Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Nengyuan Rd. Tianhe district, Guangzhou 510640 (China); Jiang, T.; Tanemura, M. [Department of Environmental Technology, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Tanemura, S. [Materials R and D Laboratory, Japan Fine Ceramics Centre, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587 (Japan); Nabatova-Gabain, N. [HORIBA Ltd., 1-7-8 Higashi-kanda, Chiyoda-ku, Tokyo (Japan); Xu, G. [Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Nengyuan Rd. Tianhe district, Guangzhou 510640 (China)

    2008-05-15

    By altering the surrounding media of metal particles, the wavelength of surface plasma resonance can be tailored, which offers the potential for utilizing of plasma resonance related phenomenon, such as photochromism. Both sandwiched (TiO{sub 2}/Ag/TiO{sub 2}) and overcoated (TiO{sub 2}/Ag) films with different thicknesses were deposited on quartz substrate by rf helicon magnetron sputtering method. The structure of multilayered TiO{sub 2}-Ag films and the concentration of loaded metal Ag in each layer were determined by spectroscopic ellipsometry in high accuracy. The spectral dependent dielectric functions of each layer were obtained, which exhibited typical semiconductor TiO{sub 2}, metal Ag and mixture TiO{sub 2}-Ag behaviors, respectively. The surface plasma resonance peak was observed for several extremely thin mixture layers. The apparent redshift of SPR peak from 700 nm to 780 nm was happened with increasing of Ag amount from 35% to 50%. The broadening of SPR peak was found for layer 3 in sample 1 with low concentration Ag embedded in TiO{sub 2} media. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Sn-Ag-Cu Nanosolders: Solder Joints Integrity and Strength

    Science.gov (United States)

    Roshanghias, Ali; Khatibi, Golta; Yakymovych, Andriy; Bernardi, Johannes; Ipser, Herbert

    2016-05-01

    Although considerable research has been dedicated to the synthesis and characterization of lead-free nanoparticle solder alloys, only very little has been reported on the reliability of the respective joints. In fact, the merit of nanoparticle solders with depressed melting temperatures close to the Sn-Pb eutectic temperature has always been challenged when compared with conventional solder joints, especially in terms of inferior solderability due to the oxide shell commonly present on the nanoparticles, as well as due to compatibility problems with common fluxing agents. Correspondingly, in the current study, Sn-Ag-Cu (SAC) nanoparticle alloys were combined with a proper fluxing vehicle to produce prototype nanosolder pastes. The reliability of the solder joints was successively investigated by means of electron microscopy and mechanical tests. As a result, the optimized condition for employing nanoparticles as a competent nanopaste and a novel procedure for surface treatment of the SAC nanoparticles to diminish the oxide shell prior to soldering are being proposed.

  16. Phase transitions in jalpaite, Ag3CuS2

    International Nuclear Information System (INIS)

    Ag3CuS2 is comprehensively studied by applying synchrotron and neutron powder diffraction as well as thermal analysis in the range from 2 K up to the melting point around 960 K. The unique sequence of the reversible phase transitions P-based 110 K/↔ I41/a 250K/↔I 41/amd 387 K/↔ Im3-barm 483 K/reversible Im3'barm+Fm3-barm 549 K/reversible Fm3'barm was detected prior to the sample's melting. The transitions at 110, 387 and 483-549 K are found to be of first order, whereas the transition at 250 K is a second-order one. The major change in the structure of jalpaite resulting from the I41/amd 250 K/reversible I41/a phase transition is a modification in the coordination geometry of the silver atoms. A large degree of structural disorder is stated for Fm3-barm- and Im3-barm-structured Ag3CuS2, which correlates with the high ionic conductivity within both cubic polymorphs. The thermal expansion of jalpaite shows some unusual features, i.e. a negative expansion along the c-direction in the I41/amd phase, a nonlinear expansion within the Im3-barm polymorph and an expansion increase upon entering the mixed Im3-barm+Fm3-barm region. Low-temperature specific heat data confirm first- and second-order anomalies at 110 and 250 K, respectively, and illustrate a pronounced non-Debye-like behaviour of jalpaite.

  17. Electron channeling in TiO2 coated Cu layers

    International Nuclear Information System (INIS)

    Electron transport in metal conductors with ∼5–30 nm width is dominated by surface scattering. In situ transport measurements as a function of surface chemistry demonstrate that the primary parameter determining the surface scattering specularity is the localized surface density of states at the Fermi level N(E f). In particular, the measured sheet resistance of epitaxial Cu(001) layers with thickness d Cu = 9–25 nm increases when coated with d Ti = 0.1–4.0 monolayers (MLs) of Ti, but decreases again during exposure to 37 Pa of O2. These resistivity changes are a function of d Cu and d Ti and are due to a transition from partially specular electron scattering at the Cu surface to completely diffuse scattering at the Cu–Ti interface, and the recovery of surface specularity as the Ti is oxidized. X-ray reflectivity and photoelectron spectroscopy indicate the formation of a 0.47 ± 0.03 nm thick Cu2O surface layer on top of the TiO2–Cu2O during air exposure, while density functional calculations of TiOx cap layers as a function of x = 0–2 and d Ti = 0.25–1.0 ML show a reduction of N(E f) by up to a factor of four. This reduction is proposed to be the key cause for the recovery of surface specularity and results in electron confinement and channeling in the Cu layer upon Ti oxidation. Transport measurements at 293 and 77 K confirm the channeling and demonstrate the potential for high-conductivity metal nanowires by quantifying the surface specularity parameter p = 0.67 ± 0.05, 0.00 ± 0.05, and 0.35 ± 0.05 at the Cu–vacuum, Cu–Ti, and Cu–TiO2 interfaces. (paper)

  18. The molecular dynamic study of anharmonic effects at Cu(111) and Ag(111) surfaces in the presence of Cu- and Ag-trimer island

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Zulfiqar Ali [Department of Physics, Hazara University, Mansehra 21300 (Pakistan); Hayat, Sardar Sikandar, E-mail: sikandariub@yahoo.com [Department of Physics, Hazara University, Mansehra 21300 (Pakistan); Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63120 (Pakistan); Rehman, Z. [Department of Physics, Hazara University, Mansehra 21300 (Pakistan); Bouafia, Farida [LMPM, Mechanical Engineering Department, University of Sidi Bel Abbes, Sidi Bel Abbes 22000 (Algeria)

    2014-05-01

    The molecular dynamics (MD) technique based on semi-empirical potentials, is used to carry out the diffusion of Cu- and Ag-trimer on Cu- and Ag(111) surface at 300, 500 and 700 K temperatures. The constant energy MD simulation elaborates the anharmonic effects at the surface such as fissures, dislocations and vacancy creation, in the presence of island. The fissures and dislocations formed are in the range of 1.5–4 Å and 1–7 Å, respectively, from the island's position. The Cu and Ag islands both diffuse easily on Cu(111) surface, manipulate that the trend of diffusion is faster on Cu surface as compared to Ag surface. The process of breaking and opening of the island has also been observed. Moreover, a surface atom popped-up at 700 K by creating a vacancy near the Cu island on Ag surface. The rate of diffusion increases with the increase in temperature, both for homo- and hetero-cases.

  19. Evaluation of Ti-Cr-Cu alloys for dental applications

    Science.gov (United States)

    Koike, Marie; Okabe, Toru; Itoh, Masayuki; Okuno, Osamu; Kimura, Kohei; Takeda, Osamu; Okabe, Toru H.

    2005-12-01

    This study examined the characteristics of as-cast Ti-Cr(7 19%)-Cu(3 7%) (all percentages in this article are mass%) alloys to evaluate their suitability for dental applications; studies on the alloy structures and mechanical properties, grindability, and corrosion behavior were included in the investigation. The alloys were centrifugally cast and bench-cooled in investment molds. The x-ray diffractometry of the as-cast alloys bench-cooled in the molds indicated the following phases: α+β+ω in the 7% Cr and 7% Cr+3% Cu; β+ω in the 13%Cr; and β in the 13%Cr+3% Cu through the 19%Cr+3% Cu alloys. The strengths of the binary β Ti-Cr and ternary β Ti-Cr-Cu alloys with 13 and 19% Cr were approximately two times higher than those of CP Ti. The alloy ductility was dependent on the chemical composition and thus, the microstructure. The 7% Cr alloys were extremely brittle and hard due to the ω phase, but the ductility was restored in the 13 and 19% Cr alloys. The hardness (HV) of the cast 13 and 19% Cr alloys was approximately 300 350 compared with a value of 200 for CP Ti. The grindability of the cast alloys was examined using a rotating SiC wheel at speeds (circumferential) of 500 and 1250 m/min. At the higher speed, the grindability of the 13 and 19% Cr alloys increased with the Cu content. The grindability of the 13% Cr alloy with 7% Cu was similar to that of CP Ti. Evaluation of the corrosion behavior in an artificial saliva revealed that the alloys are like many other titanium alloys within the normal intraoral oxidation potential. The wear resistance testing of these alloys also showed favorable results.

  20. Corrosion behaviour of amorphous Ti48Cu52, Ti50Cu50 and Ti60Ni40 alloys investigated by potentiodynamic polarization method

    Indian Academy of Sciences (India)

    A Dhawan; S Roychowdhury; P K De; S K Sharma

    2003-10-01

    Potentiodynamic polarization studies were carried out on virgin specimens of amorphous alloys Ti48Cu52, Ti50Cu50 and Ti60Ni40 in 0.5 M HNO3, 0.5 M H2SO4 and 0.5 M NaOH aqueous media at room temperature. The value of the corrosion current density (corr) was maximum for Ti48Cu52 alloy in all the three aqueous media as compared to the remaining two alloys. The value of corr for the alloy Ti48Cu52 was maximum (corr = 2.6 × 10-5 A/cm2) in 0.5 M H2SO4 and minimum (corr = 3.5 × 10-6 A/cm2) in 0.5 M NaOH aqueous solutions. In contrast, the alloy Ti60Ni40 exhibited the least corrosion current density in 0.5 M HNO3 (corr = 4.0 × 10-7 A/cm2) and in 0.5 M NaOH (corr = 5.5 × 10-7 A/cm2) aqueous media as compared to those for Ti–Cu alloys, while its value in 0.5 M H2SO4 was comparable to that for Ti50Cu50. It is suggested that the alloy Ti60Ni40 is more corrosion resistant than the alloys Ti48Cu52 and Ti50Cu50 in all the three aqueous media.

  1. Microstructure and strength of brazed joints of TiB2 cermet to TiAl-based alloys

    Institute of Scientific and Technical Information of China (English)

    李卓然; 冯吉才; 曹健

    2003-01-01

    In this study, TiB2 cermet and TiAl-based alloy are vacuum brazed successfully by using Ag-Cu-Ti filler metal. The microstructural analyses indicate that two reaction products, Ti(Cu, Al)2 and Ag based solid solution (Ag(s.s)), are present in the brazing seam, and the interface structure of the brazed joint is TiB2/TiB2+ Ag(s.s) /Ag(s.s)+Ti(Cu, Al)2/Ti(Cu, Al)2/TiAl. The experimental results show that the shear strength of the brazed TiB2/TiAl joints decreases as the brazing time increases at a definite brazing temperature. When the joint is brazed at 1 223 K for 5 min, a joint strength up to 173 MPa is achieved.

  2. Synthesis and study of plasmon-induced carrier behavior at Ag/TiO2 nanowires.

    Science.gov (United States)

    Li, Haiyan; Lu, Wenbo; Tian, Jingqi; Luo, Yonglan; Asiri, Abdullah M; Al-Youbi, Abdulrahman O; Sun, Xuping

    2012-07-01

    Nanocomposites of Ag/TiO(2) nanowires with enhanced photoelectrochemical performance have been prepared by a facile solvothermal synthesis of TiO(2) nanowires and subsequent photoreduction of Ag(+) ions to Ag nanoparticles (AgNPs) on the TiO(2) nanowires. The as-prepared nanocomposites exhibited significantly improved cathodic photocurrent responses under visible-light illumination, which is attributed to the local electric field enhancement of plasmon resonance effect near the TiO(2) surface rather than by the direct transfer of charge between the two materials. The visible-light-driven photocatalytic performance of these nanocomposites in the degradation of methylene blue dye was also studied, and the observed improvement in photocatalytic activity is associated with the extended light absorption range and efficient charge separation due to surface plasmon resonance effect of AgNPs. PMID:22639235

  3. Ethylene glycol-based Ag plating for the wet chemical fabrication of one micrometer Cu/Ag core/shell particles

    International Nuclear Information System (INIS)

    Highlights: • Cu@Ag particles less than one micrometer were fabricated through Ag polyol-plating. • Ag polyol-plating was tried without using additional reagents on Cu core particles. • Continuity, uniformity, and thickness of the Ag shell depended on plating conditions. • The sample showed an excellent oxidation initiation temperature of 280 °C. • Anti-oxidation properties of Cu@Ag powders strongly depend on the Ag shell thickness. - Abstract: With the aim of preparing an inexpensive metal filler that can be added to conductive adhesives used in fine-pitch electronic applications, a polyol solution was used to fabricate Ag-coated Cu (Cu@Ag) particles with a size on the order of one micron without the need for additional reagents. The continuity, uniformity, and thickness of the Ag shell were found to be strongly dependent on the plating conditions, particularly the reaction temperature. The Ag shell prepared at a peak temperature of 180 °C from a precursor with an initial Ag concentration of 15 wt.% was judged to be an optimum one. This same sample also showed an excellent oxidation initiation temperature of approximately 280 °C. It was inferred that the oxidation resistance of the Cu@Ag powder is largely determined by the continuity, uniformity and thickness of the Ag shell

  4. Cu/Ag-based bifunctional nanoparticles obtained by one-pot laser-assisted galvanic replacement

    International Nuclear Information System (INIS)

    We have prepared, for the first time, stable and uncapped Ag/Cu-based bifunctional nanoparticles (NPs) (BFNPs) in water, by combining ps laser ablation in liquid environment and galvanic replacement. The particles were obtained in a single step by 1,064 nm irradiation of a Cu target in water solutions of AgNO3 or AgNO2. Under proper salt concentration and irradiation conditions, the laser beam activates formation of deep orange colloids, which are positively charged and stable for weeks. High resolution transmission electron microscopy (HRTEM) analysis showed a predominance of composite crystalline nanostructures with size in the 1–15 nm range and consisting of fcc Ag and fcc Cu (or its oxides). While CuO tenorite crystalline phase was detected by HRTEM, X-ray photoelectron spectroscopy analysis permitted to observe also the Cu(I) oxidation state of Cu, being the Cu(I)/Cu(II) ratio different in the samples obtained in AgNO3 or AgNO2 baths. Functionalization with organic ligands and subsequent Raman tests demonstrated the SERS activity of the BFNPs and the existence of different complexing surface sites.

  5. Influence of the surface properties on bactericidal and fungicidal activity of magnetron sputtered Ti-Ag and Nb-Ag thin films.

    Science.gov (United States)

    Wojcieszak, D; Mazur, M; Kaczmarek, D; Mazur, P; Szponar, B; Domaradzki, J; Kepinski, L

    2016-05-01

    In this study the comparative investigations of structural, surface and bactericidal properties of Ti-Ag and Nb-Ag thin films have been carried out. Ti-Ag and Nb-Ag coatings were deposited on silicon and fused silica substrates by magnetron co-sputtering method using innovative multi-target apparatus. The physicochemical properties of prepared thin films were examined with the aid of X-ray diffraction, grazing incidence X-ray diffraction, scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy methods. Moreover, the wettability of the surface was determined. It was found that both, Ti-Ag and Nb-Ag thin films were nanocrystalline. In the case of Ag-Ti film presence of AgTi3 and Ag phases was identified, while in the structure of Nb-Ag only silver occurred in a crystal form. In both cases the average size of crystallites was ca. 11nm. Moreover, according to scanning electron microscopy and atomic force microscopy investigations the surface of Nb-Ag thin films was covered with Ag-agglomerates, while Ti-Ag surface was smooth and devoid of silver particles. Studies of biological activity of deposited coatings in contact with Bacillus subtilis, Pseudomonas aeruginosa, Enterococcus hirae, Klebisiella pneumoniae, Escherichia coli, Staphylococcus aureus and Candida albicans were performed. It was found that prepared coatings were bactericidal and fungicidal even in a short term-contact, i.e. after 2h. PMID:26952401

  6. LEEM study of nucleation, growth, and decay of Ag nanowires on Cu(110)

    Science.gov (United States)

    Senevirathne, Indrajith; Bussmann, Ezra; Kellogg, Gary; Kurtz, Richard; Sprunger, Phillip

    2007-03-01

    Low energy electron microscopy (LEEM) has been used to study the nucleation, growth, and ripening of Ag nanowires on Cu(110). Previous STM and LEED studies of Ag on the Cu(110) surface have shown that for a Ag coverage of below 0.3 ML, Ag forms a surface alloy, followed by the formation of a 2D Ag(111) flat superstructure through dealloying at one monolayer. For Ag coverages above 1.3 ML , nanowires of Ag(110), with widths/heights of 12 nm / 2nm, grow along the [110] crystallographic direction with highly anisotropic aspect ratios. LEEM reveals that Ag initially alloys at Cu/Ag step edges producing a distortion of the steps. Upon deposition above 1 ML, nucleation of Ag nanowires was observed across terraces, however nucleation still occurred at defect and step edges. LEEM showed that the nanowires grow to micron lengths and have highly anisotropic aspect ratios. Annealing above 573K resulted in rapid Oswald ripening of nanowires to Ag clusters of several micron dimensions. Quantitative details of the growth and decay mechanisms will be discussed. Sandia Corporation is a Lockheed Martin Company, for the US DOE's NNSA under Contract DE-AC04-94AL85000. Work was supported CINT-U2006A123 and NSF-DMR-0504654.

  7. Synthesis, characterization and multifunctional properties of plasmonic Ag-TiO2 nanocomposites.

    Science.gov (United States)

    Prakash, Jai; Kumar, Promod; Harris, R A; Swart, Chantel; Neethling, J H; van Vuuren, A Janse; Swart, H C

    2016-09-01

    We report on the synthesis of multifunctional Ag-TiO2 nanocomposites and their optical, physio-chemical, surface enhanced Raman scattering (SERS) and antibacterial properties. A series of Ag-TiO2 nanocomposites were synthesized by sol-gel technique and characterized by x-ray diffraction, scanning and transmission electron microscopy, energy-dispersed x-ray analysis, photoluminescence, UV-vis, x-ray photoelectron and Raman spectroscopy and Brunauer-Emmett-Teller method. The Ag nanoparticles (NPs) (7-20 nm) were found to be uniformly distributed around and strongly attached to TiO2 NPs. The novel optical responses of the nanocomposites are due to the strong electric field from the localized surface plasmon (LSP) excitation of the Ag NPs and decreased recombination of photo-induced electrons and holes at Ag-TiO2 interface providing potential materials for photocatalysis. The nanocomposites show enhancement in the SERS signals of methyl orange (MO) molecules with increasing Ag content attributed to the long-range electromagnetic enhancement from the excited LSP of the Ag NPs. To further understand the SERS activity, molecular mechanics and molecular dynamics simulations were used to study the geometries and SERS enhancement of MO adsorbed onto Ag-TiO2 respectively. Simulation results indicate that number of ligands (MO) that adsorb onto the Ag NPs as well as binding energy per ligand increases with increasing NP density and molecule-to-surface orientation is mainly flat resulting in strong bond strength between MO and Ag NP surface and enhanced SERS signals. The antimicrobial activity of the Ag-TiO2 nanocomposites was tested against the bacterium Staphylococcus aureus and enhanced antibacterial effect was observed with increasing Ag content explained by contact killing action mechanism. These results foresee promising applications of the plasmonic metal-semiconductor based nano-biocomposites for both chemical and biological samples. PMID:27456278

  8. Comparative study of LiF:Mg,Cu,Na,Si and Li2B4O7:Cu,Ag,P TL detectors

    International Nuclear Information System (INIS)

    Recently, two new types of 'tissue equivalent' thermoluminescent detectors (TLDs) have aroused attention: LiF:Mg,Cu,Na,Si and Li2B4O7:Cu,Ag,P. In this work the characteristics of both detectors were compared with the characteristics of the well-known type LiF:Mg,Ti detector, TLD-100. The following properties were investigated: The glow curve structures, relative sensitivity, batch homogeneity and uniformity, detection threshold, reproducibility of the response, linearity in the wide dose range and fading. Also, the energy dependence for medium and low energy X-rays was determined in the range of mean energies between 33 and 116 keV. The results confirmed 'tissue equivalency' of both new types in the investigated range of photon energies. LiF:Mg,Cu,Na,Si detector has very high sensitivity (∼75 times higher than that of TLD-100) and is convenient for use in a very low range of doses. Li2B4O7:Cu,Ag,P detector shows some improvements in comparison with the previously prepared types of lithium borate. The most important is the five times higher sensitivity than that of TLD-100. This detector is also very promising, especially in medical dosimetry. (authors)

  9. Temperature Induced Degradation of Nb Ti/Cu Composite Superconductors

    CERN Document Server

    Scheuerlein, C; Senatore, C; Di Michiel, M; Thilly, L; Gerardin, A; Reluner, B; Oberli, L; Willering, G; Bottura, L

    2009-01-01

    The degradation mechanisms of state-of-the-art Nb-Ti/Cu superconductors are described, based on in-situ synchrotron X-ray diffraction measurements during heat treatment. A quantitative description of the Nb-Ti/Cu degradation in terms of critical current density, Cu stabiliser resistivity and mechanical composite strength is presented. In an applied magnetic field a significant critical current degradation is already observed after a 5-minute 400 °C heat treatment, due to variations of a-Ti precipitate size and distribution within the Nb-Ti alloy filaments. A strong degradation of the strand mechanical properties is observed after several minutes heating above 550 °C, which is also the temperature at which the formation of Cu Ti intermetallic phases is detected. Several minutes heating at 250 °C are sufficient to increase the RRR of the strongly cold work strands inside a Rutherford type cable from about 80 to about 240. Heating for several minutes at 400 °C does not cause a significant conductor degradati...

  10. Structural study of Zr-Cu-Ag bulk metallic glasses using the anomalous X-ray scattering method

    International Nuclear Information System (INIS)

    The structures of Zr45Cu45Ag10 and Zr40Cu40Ag20 bulk metallic glasses (BMGs) were investigated using the anomalous x-ray scattering and reverse Monte Carlo simulation (AXS-RMC) method. The fundamental structural features of Zr45Cu45Ag10 and Zr40Cu40Ag20 can be properly demonstrated through the common dense random packing of the hard spheres, and the addition of Ag appeared to result in no prominent formation of the particular chemical ordering units. A Voronoi analysis indicated that the fraction of the icosahedron-like coordination was the largest around the Cu in Zr45Cu45Ag10 BMG, where the best glass-forming ability was realized. The improvement in the glass-forming ability in a Zr-Cu-Ag system appears to be associated with the icosahedron-like local coordination.

  11. Characterization of Cu3P phase in Sn3.0Ag0.5Cu0.5P/Cu solder joints

    Institute of Scientific and Technical Information of China (English)

    Jian-xun Chen; Xing-ke Zhao; Xu-chen Zou; Ji-hua Huang; Hai-chun Hu; Hai-lian Luo

    2014-01-01

    This article reports the effects of phosphorus addition on the melting behavior, microstructure, and mechanical properties of Sn3.0Ag0.5Cu solder. The melting behavior of the solder alloys was determined by differential scanning calorimetry. The interfacial micro-structure and phase composition of solder/Cu joints were studied by scanning electron microscopy and energy dispersive spectrometry. Thermodynamics of Cu-P phase formation at the interface between Sn3.0Ag0.5Cu0.5P solder and the Cu substrate was characterized. The results indicate that P addition into Sn3.0Ag0.5Cu solder can change the microstructure and cause the appearance of rod-like Cu3P phase which is distributed randomly in the solder bulk. The Sn3.0Ag0.5Cu0.5P joint shows a mixture of ductile and brittle fracture after shear test-ing. Meanwhile, the solidus temperature of Sn3.0Ag0.5Cu solder is slightly enhanced with P addition.

  12. Characterization of Cu3P phase in Sn3.0Ag0.5Cu0.5P/Cu solder joints

    Science.gov (United States)

    Chen, Jian-xun; Zhao, Xing-ke; Zou, Xu-chen; Huang, Ji-hua; Hu, Hai-chun; Luo, Hai-lian

    2014-01-01

    This article reports the effects of phosphorus addition on the melting behavior, microstructure, and mechanical properties of Sn3.0Ag0.5Cu solder. The melting behavior of the solder alloys was determined by differential scanning calorimetry. The interfacial microstructure and phase composition of solder/Cu joints were studied by scanning electron microscopy and energy dispersive spectrometry. Thermodynamics of Cu-P phase formation at the interface between Sn3.0Ag0.5Cu0.5P solder and the Cu substrate was characterized. The results indicate that P addition into Sn3.0Ag0.5Cu solder can change the microstructure and cause the appearance of rod-like Cu3P phase which is distributed randomly in the solder bulk. The Sn3.0Ag0.5Cu0.5P joint shows a mixture of ductile and brittle fracture after shear testing. Meanwhile, the solidus temperature of Sn3.0Ag0.5Cu solder is slightly enhanced with P addition.

  13. Structural, morphological, optical and photocatalytic investigation of Ag-doped TiO2

    Science.gov (United States)

    Kundu, Virender Singh; Singh, Davender; Maan, A. S.; Tanwar, Amit

    2016-05-01

    The pure and Ag-doped TiO2 nanoparticles were prepared by using Titanium isoproxide (TTIP), silver nitrate sodium hydroxide and sodium hydroxide. The calcined nanoparticles at 400°C were characterized by means of X-ray diffraction (XRD). XRD analyses reveal that the nanoparticles of various doping concentration were having anatase phase. The particle size was calculated by Scherrer formula and was found 11.08 nm for pure TiO2 and 8.86 nm for 6 mol % Ag doped TiO2. The morphology and nature of nanoparticles was analyzed by using scanning electron microscope (SEM), the optical absorption spectra of pure TiO2 and Ag-doped TiO2 nanoparticles showed that absorption edge increases towards longer wavelength from 390 nm (pure) to 450 nm (doped), also band gap energy calculated from Tauc's plot decrease from 3.20eV to 2.92eV with increase in doing. The measurement of photocatalytic properties of pure TiO2 and Ag-doped TiO2 nanoparticles showed that Ag-doped TiO2 degrades MB dye more efficiently than pure TiO2.

  14. HRTEM studies of amorphous ZrNiTiCu nanocrystalline composites.

    Science.gov (United States)

    Dutkiewicz, J; Lityńska-Dobrzyńska, L; Kovacova, A; Molnarova, M; Rogal, L; Maziarz, W

    2010-03-01

    Ball milling of easy glass forming Ti(25)Zr(17)Ni(29)Cu(29) alloys lead to the formation of an amorphous structure accompanied by a substantial increase of powder microhardness. The powders show clear glass transition effect and a few stage crystallization starting above 500 degrees C. High-resolution transmission electron microscope technique allowed identifying nanocrystalline inclusions as Cu(12)NiTi(7) within the amorphous powder. The amorphous powders mixed with nanocrystalline iron or silver powders were hot pressed to form composites. A narrow 200 nm broad intermediate single-phase layer at the amorphous-phase/iron interface containing all elements present in the composite was identified using transmission electron microscope and high-angle annular dark field detector techniques. scanning transmission electron microscopy energy dispersive spectroscopy line profile showed gradual change of composition within the intermediate zone. Amorphous phase contains small nanocrystals of size close to 10 nm identified using High-resolution transmission electron microscope as Cu(12)NiTi(7.) Compression tests have shown better plasticity of composites than in the case of pure hot-pressed amorphous powder; furthermore, high elastic limit of composites and the ultimate compression stress of about 1800 MPa for composites containing 20% Fe and near 700 MPa for those with 20% Ag. PMID:20500372

  15. Effects of water absorption of dielectric underlayers on Al-Si-Cu film properties and electromigration performance in Al-Si-Cu/Ti/TiN/Ti interconnects

    Science.gov (United States)

    Yoshida, Tomoyuki; Hashimoto, Shoji; Ohwaki, Takeshi; Mitsushima, Yasuichi; Taga, Yasunori

    1998-01-01

    The effects of underlying dielectric (phosphosilicate glass and borophosphosilicate glass) films to a humid air ambient on Al-Si-Cu film properties and electromigration (EM) performance in Al-Si-Cu/Ti/TiN/Ti layered films have been investigated as a function of the boron content and exposure time of the dielectric films. The Al(111) orientation in the layered films was found to improve drastically with increasing boron content and exposure time. The full width at half maximum value of an Al(111) x-ray rocking curve reached less than 1°. It was also found that the Al-Si-Cu surface becomes smoother and grain sizes increase as the Al(111) orientation improves. The improved Al(111) orientation was attributed to the improved Ti(002) orientation of the bottom Ti films. Further, it was demonstrate that interconnects fabricated from the improved layered film have excellent EM performance.

  16. In situ quantitative study of microstructural evolution at the interface of Sn3.0Ag0.5Cu/Cu solder joint during solid state aging

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hailong [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); An, Rong, E-mail: anr@hit.edu.cn [Key Laboratory of Micro-systems and Micro-structures Manufacturing, Harbin Institute of Technology, Ministry of Education, Harbin 150080 (China); Wang, Chunqing; Jiang, Zhi [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China)

    2015-06-15

    Highlights: • Cu dissolution during reflowing was mainly occurred under the gaps between scallops. • Though IMC growth was diffusion-controlled, consumption of Cu substrate was not. • Growth of Cu{sub 3}Sn layer in Sn3.0Ag0.5Cu/Cu solder joint was on the both sides. • Ag and Cu lead to a thinner Cu{sub 3}Sn layer due to inhibit the diffusion of Sn into Cu. - Abstract: In situ microstructural evolution at the interface of Sn3.0Ag0.5Cu/Cu solder joint during solid state aging was quantitatively studied by nanoindentation. The morphology of Cu{sub 6}Sn{sub 5} gradually altered from scallop type to layer type. Though the growth of IMCs was diffusion-controlled, the consumption of Cu substrate was not linear with the square root of aging time. At the initial stage of solid state aging, the Cu atoms essential to the growth of IMCs were mainly from the supersaturated solder matrix. When the Cu atoms from supersaturated solder matrix were exhausted, the Cu atoms for the growth of IMCs were primarily from the Cu substrate. In addition, the IMCs formed at this state were principally used to fill up the gaps between scallops. After the gaps disappeared, the consumption of Cu substrate slowed down. Furthermore, the growth of Cu{sub 3}Sn layer in Sn3.0Ag0.5Cu/Cu solder joint was on the both sides with layer type. Since the Sn atoms were inhibited to diffuse into the Cu substrate by the alloying elements of Ag and Cu, the thickness of Cu{sub 3}Sn layer in SnAgCu/Cu solder joint was much thinner than that in pure Sn/Cu solder joint.

  17. In situ quantitative study of microstructural evolution at the interface of Sn3.0Ag0.5Cu/Cu solder joint during solid state aging

    International Nuclear Information System (INIS)

    Highlights: • Cu dissolution during reflowing was mainly occurred under the gaps between scallops. • Though IMC growth was diffusion-controlled, consumption of Cu substrate was not. • Growth of Cu3Sn layer in Sn3.0Ag0.5Cu/Cu solder joint was on the both sides. • Ag and Cu lead to a thinner Cu3Sn layer due to inhibit the diffusion of Sn into Cu. - Abstract: In situ microstructural evolution at the interface of Sn3.0Ag0.5Cu/Cu solder joint during solid state aging was quantitatively studied by nanoindentation. The morphology of Cu6Sn5 gradually altered from scallop type to layer type. Though the growth of IMCs was diffusion-controlled, the consumption of Cu substrate was not linear with the square root of aging time. At the initial stage of solid state aging, the Cu atoms essential to the growth of IMCs were mainly from the supersaturated solder matrix. When the Cu atoms from supersaturated solder matrix were exhausted, the Cu atoms for the growth of IMCs were primarily from the Cu substrate. In addition, the IMCs formed at this state were principally used to fill up the gaps between scallops. After the gaps disappeared, the consumption of Cu substrate slowed down. Furthermore, the growth of Cu3Sn layer in Sn3.0Ag0.5Cu/Cu solder joint was on the both sides with layer type. Since the Sn atoms were inhibited to diffuse into the Cu substrate by the alloying elements of Ag and Cu, the thickness of Cu3Sn layer in SnAgCu/Cu solder joint was much thinner than that in pure Sn/Cu solder joint

  18. Cu-Ag core-shell nanoparticles with enhanced oxidation stability for printed electronics

    Science.gov (United States)

    Lee, Changsoo; Kim, Na Rae; Koo, Jahyun; Jong Lee, Yung; Lee, Hyuck Mo

    2015-11-01

    In this work, we synthesized uniform Cu-Ag core-shell nanoparticles using a facile two-step process that consists of thermal decomposition and galvanic displacement methods. The core-shell structure of these nanoparticles was confirmed through characterization using transmission electron microscopy, energy-dispersive spectroscopy, and x-ray diffraction. Furthermore, we investigated the oxidation stability of the Cu-Ag core-shell nanoparticles in detail. Both qualitative and quantitative x-ray photoelectron spectroscopy analyses confirm that the Cu-Ag core-shell nanoparticles have considerably higher oxidation stability than Cu nanoparticles. Finally, we formulated a conductive ink using the synthesized nanoparticles and coated it onto glass substrates. Following the sintering process, we compared the resistivity of the Cu-Ag core-shell nanoparticles with that of the Cu nanoparticles. The results of this study clearly show that the Cu-Ag core-shell nanoparticles can potentially be used as an alternative to Ag nanoparticles because of their superior oxidation stability and electrical properties.

  19. YBa2Cu3O(7-x)-Ag composites prepared by the coprecipitation route

    International Nuclear Information System (INIS)

    The precursor powders to yield composites of YBa2Cu3O(7-x) and Ag (in variable amounts) were obtained by the oxalate coprecipitation technique to obtain a homogeneous dispersion of Ag in YBa2Cu3O(7-x) matrix. The Ag content was varied between one and 30 percent by weight of the nominal composition YBa2Cu3O(6.5). X-ray powder diffraction results indicate a progressive decrease in the intensities of characteristic peaks of the orthorhombic superconducting phase with increasing Ag amount. Bars pressed from these powders were evaluated with respect to transition temperature, current density, contact resistivity, bulk density, and microstructure. A maximum current density of 766 A/sq cm is measured on a sample containing 30 percent by weight of Ag. 9 refs

  20. Ag induced structures on an oxygen pre-covered Cu(110) surface

    International Nuclear Information System (INIS)

    Full text: The Cu(110) surface can be readily structured by adsorbing oxygen: if the coverage of oxygen is less than required to form a complete (2x1) overlayer, CuO stripes are formed which are separated by bare copper areas. These stripes are uniformly distributed and parallel to the [001] direction. On such an oxygen pre-covered surface silver was adsorbed at 660 K. As revealed by scanning tunneling microscopy, submonolayer silver coverages lead to a phase separation between CuO and Ag/Cu alloy areas. The original Cu-CuO stripe phase is destroyed and larger CuO areas ('ponds') are formed. They are separated by Ag like stripes which are again parallel to the [001] direction. The use of this structure as a template for additional adsorption of Ag at 300 K leads to the formation of 3D nanorods along the perpendicular [1-10] direction as known for Ag grown on clean Cu(110). Since on our template the nanorods only grow on the Ag like stripes, their length is limited by the width of these stripes. With this technique one can even change the aspect ratio of the rods such that their longer axis is now parallel to the [001] direction. (author)

  1. Phase composition of rapidly solidified Ag-Sn-Cu dental alloys

    International Nuclear Information System (INIS)

    The phase composition of some rapidly solidified Ag-Sn-Cu dental alloys with different copper contents (6.22 wtpct) has been studied by XRD, EMPA and optical microscopy. The samples were prepared from melt-spun ribbons. The microstructure of the as-quenched ribbons was microcrystalline and consisted of the Ag sub 3 Sn, Ag sub 4 Sn, Cu sub 3 Sn and Cu sub 3 Sn sub 8 phases. Mixing with mercury (amalgamation) led to formation of the Ag sub 2 Hg sub 3, Sn sub 7 Hg and Cu sub 6 Sn sub 5 phases. The amount of copper atoms in the alloys played an important role in phase formation in the amalgams

  2. New bulk glassy alloys in Cu-Zr-Ag ternary system prepared by casting and milling

    International Nuclear Information System (INIS)

    The thermal stability, crystallization behaviour and glass forming ability of Cu-Zr-Ag system have been investigated on the basis of a ternary phase diagram. We altered the concentration of the alloys from the Cu58Zr42 to the concentration of the deep eutectic point of the Cu-Zr-Ag ternary system and we calculated the glass forming ability parameters. This paper summarises the results of the procedure during which Cu-Zr-Ag amorphous alloys with different Ag content (0-25%) were prepared by casting and ball-milling. Wedge-shaped samples were prepared from the ingots by centrifugal casting into copper mold. The supercooled liquid region (ΔTx) exceeded 75K. Following the characterization of the cast alloys, master alloys of identical composition were milled in a Fritsch Pulverisette 2 ball-mill. The powders, milled for various periods of time were analysed by XRD in order to define the amorphous fraction.

  3. On the ternary AgCu – Ga system: Electromotive force measurement and thermodynamic modeling

    Energy Technology Data Exchange (ETDEWEB)

    Gierlotka, Wojciech, E-mail: wojtek@mail.ndhu.edu.tw [Materials Science and Engineering Department, National Dong Hwa University, Hualien, Taiwan (China); Jendrzejczyk-Handzlik, Dominika; Fitzner, Krzysztof; Handzlik, Piotr [Non-Ferrous Metals Department, AGH University of Science and Technology, Krakow (Poland)

    2015-10-15

    The ternary silver–copper–gallium system found application as a solder material in jewel crafting and electronics, thus a phase diagram of this system seems to be important tool, which is necessary for a proper application of different alloys. The activity of gallium in liquid phase was determined by electromotive measurement technique and after that the equilibrium diagram of AgCu – Ga was modeled based on available experimental data using Calphad approach. A set of Gibbs energies was found and used for calculation a phase diagram and thermodynamic properties of liquid phase. The experimental data was reproduced well by calculation. - Highlights: • For the first time activity of Ga in liquid AgCu – Ga alloys was measured. • For the first time the ternary AgCu – Ga system was thermodynamically modeled. • Modeled AgCu – Ga system reproduces experimental data well.

  4. Antimicrobial activity and biocompatibility of Ag+- and Cu2+-doped biphasic hydroxyapatite/α-tricalcium phosphate obtained from hydrothermally synthesized Ag+- and Cu2+-doped hydroxyapatite

    International Nuclear Information System (INIS)

    Hydroxyapatite (HAp) powders doped with Ag+ or Cu2+ were synthesized by a hydrothermal method in order to obtain biomaterial with an antimicrobial effect. The synthesis was performed with two contents of dopant (Ag+ or Cu2+) by considering both the antimicrobial activities and biocompatibility of the powders. The doped HAp was annealed at 1200 °C for 2 h with the intention of investigating the influence of doping with Ag+ and Cu2+ on the creation of the biphasic HAp/α-tricalcium phosphate (HAp/α-TCP) and determining the antimicrobial activity and biocompatibility of the obtained biphasic powders. Analyses of all powders, undoped and doped HAp and HAp/α-TCP, were performed by Field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), atomic absorption spectroscopy (AAS) and energy-dispersive X-ray spectroscopy (EDS). The in vitro antibacterial activities of the powders were evaluated against: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. All powders showed good antimicrobial activity but generally the powders of doped HAp/α-TCP had more uniform results against all pathogenic microorganisms than the powders of doped HAp. In vitro biocompatibility tests, MTT and DET, were used to evaluate the biocompatibility of Ag+- and Cu2+-doped HAp/α-TCP with MRC-5 human fibroblast cells. These tests confirmed that powders do not have a cytotoxic effect. The HAp/α-TCP powders doped with the lower content of Ag+ and Cu2+ showed especially good biocompatibility. Antimicrobial and biocompatibility tests recommend the Ag+- and Cu2+-doped HAp/α-TCP as promising material for use in reconstructive surgery of bone.

  5. Low-firing Li2ZnTi3O8 microwave dielectric ceramics with BaCu(B2O5) additive

    Indian Academy of Sciences (India)

    Guo-Hua Chen; Jin Liu; Xu-Qiong Li; Hua-Rui Xu; Min-Hong Jiang; Chang-Rong Zhou

    2011-10-01

    Phase purity, microstructure, sinterability and microwave dielectric properties of BaCu(B2O5)-added Li2ZnTi3O8 ceramics and their cofireability with Ag electrode were investigated. A small amount of BaCu (B2O5) can effectively reduce the sintering temperature from 1075°C to 925°C, and it does not induce much degradation of the microwave dielectric properties. Microwave dielectric properties of r = 23.1, × = 22,732 GHz and = −17.6 ppm/°C were obtained for Li2ZnTi3O8 ceramic with 1.5 wt% BaCu(B2O5) sintered at 925°C for 4 h. The Li2ZnTi3O8 +BCB ceramics can be compatible with Ag electrode, which makes it a promising microwave dielectric material for low-temperature co-fired ceramic technology application.

  6. Relationship between morphologies and orientations of Cu6Sn5 grains in Sn3.0Ag0.5Cu solder joints on different Cu pads

    International Nuclear Information System (INIS)

    The morphologies and orientations of Cu6Sn5 intermetallic compounds in the Sn3.0Ag0.5Cu solder joints both on polycrystalline and single crystal Cu pads under different peak reflow temperatures and times above liquids were investigated. The relationship between Cu6Sn5 grain orientations and morphologies was clarified. At the interface of Sn3.0Ag0.5Cu/polycrystalline Cu pad, scalloped Cu6Sn5 intermetallic compounds formed at 250 °C and roof shape Cu6Sn5 formed at 300 °C. Both scalloped Cu6Sn5 and roof shape Cu6Sn5 had a preferred orientation of (0001) plane being parallel to polycrystalline Cu pad surface. Besides, the percentage of large angle grain boundaries increased as the peak reflow temperature rose. At the interface of Sn3.0Ag0.5Cu/(111) single crystal Cu pad, the Cu6Sn5 intermetallic compounds were mainly scallop-type at 250 °C and were prism type at 300 °C. The prismatic Cu6Sn5 grains grew along the three preferred directions with the inter-angles of 60° on (111) single crystal Cu pad while along two perpendicular directions on (100) single crystal Cu pad. The orientation relationship between Cu6Sn5 grains and the single crystal Cu pads was investigated by electron backscatter diffraction technology. In addition, two types of hollowed Cu6Sn5 intermetallic compounds were found inside the joints of polycrystalline Cu pads. The long hexagonal Cu6Sn5 strips were observed in the joints reflowing at 250 °C while the hollowed Cu6Sn5 strips with the ‘▪’ shape cross-sections appeared at 300 °C, which was attributed to the different grain growth rates of different Cu6Sn5 crystal faces. - Highlights: • The orientation of interfacial Cu6Sn5 grains was obtained by EBSD technology. • Two types of hollowed Cu6Sn5 strips were found at different temperatures. • The formation mechanism of hollowed Cu6Sn5 was elaborated based on Bravais law. • The relationship between Cu6Sn5 grain orientations and morphologies was clarified

  7. Optical Limiting Properties of Ag-Cu Metal Alloy Nanoparticles Analysis by using MATLAB

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-Hua; LI Hui-Qing; LU Jian-Duo; WANG Ru-Wu

    2011-01-01

    Ag-Cu alloy nanoparticles were formed by sequential ion implantation (Ag and Cu) in silica using a metal vapor vacuum arc (MEVVA) ion source.Third-order nonlinear optical properties of the nanoparticles were measured at 1064nm excitations using the Z-scan technique.Curve fitting analysis,based on the MATLAB features for Ag-Cu alloy nanoparticle optical limiting experiments,is used.The results show that Ag-Cu alloy nanoparticles display a refractive optical limiting effect at 1064 nm.Recently,increasing attention has been focused on the third-order nonlinear susceptibility and the photorefractive effect of noble-metal clusters embedded in dielectric matrices.[1-3] Third-order nonlinearities of metal/dielectric composite materials are influenced not only by the type and size of the embedded metal clusters,but also by the dielectric constant,thermal conductivity and heat capacity of the dielectric matrices.[4-6] Amongst the nanoparticles studied earlier,high nonlinear absorption and nonlinear refraction coefficients were found in copper and copper containing nanomaterials.[7,8] For silver,the nonlinear refractive index γ changes from positive to negative upon the growth of clusters.[9] Potential applications of optical limiters in the protection of sensors from intense laser pulses have motivated great efforts to design new nonlinear optical systems.[10]%Ag-Cu alloy nanoparticles were formed by sequential ion implantation (Ag and Cu) in silica using a metal vapor vacuum arc (MEVVA) ion source. Third-order nonlinear optical properties of the nanoparticles were measured at 1064 nm excitations using the Z-scan technique. Curve fitting analysis, based on the MATLAB features for Ag-Cu alloy nanoparticle optical limiting experiments, is used. The results show that Ag-Cu alloy nanoparticles display a refractive optical limiting effect at 1064 nm.

  8. Thermodynamic properties of the liquid Ag-Bi-Cu-Sn lead-free solder alloys

    OpenAIRE

    Garzel G.; Kopyto M.; Zabdyr L.A.

    2014-01-01

    The electromotive force measurement method was employed to determine the thermodynamic properties of liquid Ag-Bi-Cu-Sn alloys using solid electrolyte galvanic cells as shown below: Kanthal+Re, Ag-Bi-Cu-Sn, SnO2 | Yttria Stabilized Zirconia | air, Pt, Experiments were made within temperature interval: 950 - 1300K along four composition paths of constant ratios: XAg : XBi : XCu = 1, XAg : (XBi + XCu) = 3:2 for XBi = XCu, XBi : (XAg + XCu) = 3:2 for XAg = XCu...

  9. Thermal Analysis of the Sn-Ag-Cu-In Solder Alloy

    DEFF Research Database (Denmark)

    Sopousek, J.; Palcut, Marián; Hodúlová, Erika;

    2010-01-01

    The tin-based alloy Sn-1.5Ag-0.7Cu-9.5In (composition in wt.%) is a potential candidate for lead-free soldering at temperatures close to 200°C due to the significant amount of indium. Samples of Sn-1.5Ag-0.7Cu-9.5In were prepared by controlled melting of the pure elements, followed by quenching...

  10. STUDY OF Ag DIFFUSION INTO Cu SINGLE CRYSTALS BY RUTHERFORD BACKSCATTERING SPECTROMETRY

    Institute of Scientific and Technical Information of China (English)

    R. Wang

    2003-01-01

    4. 0Me V 7 Li++ RBS was used for investigations of thermal diffusion of Ag in Cu single crystals. The annealing of samples was carried out in vacuum in the temperature range from 498K to 613K. The element depth concentration profiles transformed fiom RBS spectra indicate that the diffusion of Ag into Cu is a typical volume diffusion. The Arrhenius parameters corresponding to the diffusion were obtained.

  11. A highly sensitive non-enzymatic glucose sensor based on bimetallic Cu-Ag superstructures.

    Science.gov (United States)

    Li, Hua; Guo, Chun-Yan; Xu, Cai-Ling

    2015-01-15

    Bimetallic Cu-Ag superstructures were successfully fabricated for the first time by using the natural leaves as reducing agent through a facile one-step hydrothermal process. Morphology, structure and composition of the Cu-Ag superstructures were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and inductively coupled plasma-optical emission spectroscopy (ICP-OES), respectively. The results reveal that the Cu-Ag superstructure is bimetallic nanocomposite constructed by nanoparticles with low Ag content and shows a rough surface and porous flexural algae-like microstructure. By using a three-dimensional nickel foam as the scaffold, a novel non-enzymatic glucose sensor based on Cu-Ag nanocomposites has been fabricated and applied to non-enzymatic glucose detection. The as-prepared Cu-Ag nanocomposites based glucose sensor displays distinctly enhanced electrocatalytic activity compared to those obtained with pure Cu nanomaterials prepared with a similar procedure, revealing a synergistic effect of the matrix Cu and the doped Ag. Cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy indicate that the Cu-Ag superstructures based glucose sensor displays a fascinating sensitivity up to 7745.7 μA mM(-1) cm(-2), outstanding detection limit of 0.08 μM and fast amperometric response (glucose detection. Furthermore, the sensor also exhibits significant selectivity, excellent stability and reproducibility, as well as attractive feasibility for real sample analysis. Because of its excellent electrochemical performance, low cost and easy preparation, this novel electrode material is a promising candidate in the development of non-enzymatic glucose sensor. PMID:25113052

  12. Highly Efficient Photocatalytic Hydrogen Evolution in Ternary Hybrid TiO2/CuO/Cu Thoroughly Mesoporous Nanofibers.

    Science.gov (United States)

    Hou, Huilin; Shang, Minghui; Gao, Fengmei; Wang, Lin; Liu, Qiao; Zheng, Jinju; Yang, Zuobao; Yang, Weiyou

    2016-08-10

    Development of novel hybrid photocatalysts with high efficiency and durability for photocatalytic hydrogen generation is highly desired but still remains a grand challenge currently. In the present work, we reported the exploration of ternary hybrid TiO2/CuO/Cu thoroughly mesoporous nanofibers via a foaming-assisted electrospinning technique. It is found that by adjusting the Cu contents in the solutions, the unitary (TiO2), binary (TiO2/CuO, TiO2/Cu), and ternary (TiO2/CuO/Cu) mesoporous products can be obtained, enabling the growth of TiO2/CuO/Cu ternary hybrids in a tailored manner. The photocatalytic behavior of the as-synthesized products as well as P25 was evaluated in terms of their hydrogen evolution efficiency for the photodecomposition water under Xe lamp irradiation. The results showed that the ternary TiO2/CuO/Cu thoroughly mesoporous nanofibers exhibit a robust stability and the most efficient photocatalytic H2 evolution with the highest release rate of ∼851.3 μmol g(-1) h(-1), which was profoundly enhanced for more than 3.5 times with respect to those of the pristine TiO2 counterparts and commercial P25, suggesting their promising applications in clean energy production. PMID:27430307

  13. Surface-modified antibacterial TiO2/Ag+ nanoparticles: Preparation and properties

    International Nuclear Information System (INIS)

    Studies were performed on surface modification of antibacterial TiO2/Ag+ nanoparticles by grafting γ-aminopropyltriethoxysilane (APS). The interfacial structure of the modified particles was characterized by Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and thermogravimetric analysis. The thickness of the surface layer was determined by using Auger electron spectroscopy (AES). The results show that APS is chemically bonded to the surface of antibacterial TiO2/Ag+ nanoparticles. Furthermore, the modified particles were mixed in PVC to prepare composites whose antibacterial property was investigated. The results suggest that surface modification has no negative effect on antibacterial activity of TiO2/Ag+ nanoparticles and PVC-TiO2/Ag+ composites exhibits good antibacterial property

  14. Nonlinear optical properties and optical limiting measurements of graphene oxide - Ag@TiO2 compounds

    Science.gov (United States)

    Ebrahimi, M.; Zakery, A.; Karimipour, M.; Molaei, M.

    2016-07-01

    In this work Graphene Oxide (GO), Ag@TiO2 core-shells and GO-Ag@TiO2 compounds were prepared and experimentally verified. Using a low power laser diode with 532 nm wavelength, the magnitude and the sign of the nonlinear refractive index and nonlinear absorption were determined by the Z-scan technique. It was observed that the nonlinear absorption of GO-Ag@TiO2 mixture was higher than pure GO. The optical limiting effect of these samples was also investigated using the 2nd harmonics of a pulsed Nd-YAG laser at 532 nm. Our results showed that the sole Ag@TiO2 didn't show any appreciable optical limiting effect, however after just mixing with graphene oxide the threshold of optical limiting was increased and the compound showed an enhancement of optical limiting behavior compared to GO itself. The presented results are discussed and compared with other literature reports.

  15. Self-assembly of Ag-TiO2 Nanoparticles:Synthesis, Characterization and Catalytic Application

    Institute of Scientific and Technical Information of China (English)

    WANG Xin; LIU Xiaoheng; WANG Xinyun

    2012-01-01

    The formation of Ag clusters on titanium oxide (TiO2) nanoparticles was achieved by selfassembly process and calcination.The obtained nanoparticles were characterized by X-ray diffraction (XRD),transmission electron microscopy (TEM),and ultraviolet visible spectroscopy (UV-Vis),and conventional techniques (XRD,TEM and UV-Vis) were used to identify Ag particles on the TiO2 surfaces.The results show that Ag-TiO2 particles can be applied to improve catalytic activity of the epoxidation of styrene oxides.Styrene oxide is the main product of catalytic reaction with H2O2 as the oxidant by using Ag-TiO2 nanoparticles as catalysts.High catalytic activitity of styrene oxide can be obtainable at 80 ℃.The reaction temperature,reaction time,the molar ratio of H2O2/styrene and solvent affect greatly the catalytic epoxidation of styrene.

  16. New Ti-based Ti–Cu–Zr–Fe–Sn–Si–Ag bulk metallic glass for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Shujie; Liu, Ying; Li, Haifei; Sun, Lulu [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Li, Yan [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Beijing Key Laboratory for Advanced Functional Materials and Thin Film Technology, Beihang University, Beijing 100191 (China); Zhang, Tao, E-mail: zhangtao@buaa.edu.cn [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China)

    2015-03-15

    Highlights: • Novel Ti{sub 47}Cu{sub 38}Zr{sub 7.5}Fe{sub 2.5}Sn{sub 2}Si{sub 1}Ag{sub 2} (at.%) bulk metallic glass (BMG) with a critical diameter of 7 mm was discovered. • The present BMG is the largest Ni- and Be-free Ti-based BMG containing low content of noble metal reported to date. • The glassy alloy possesses high specific strength, low Young’s modulus, and good corrosion resistance and bio-compatibility. • Combination of high glass-forming ability and good mechano- and bio-compatibility for the Ti-based BMG demonstrates the potential for use in biomedical applications. - Abstract: A novel Ni-free Ti{sub 47}Cu{sub 38}Zr{sub 7.5}Fe{sub 2.5}Sn{sub 2}Si{sub 1}Ag{sub 2} (at.%) bulk metallic glass (BMG) with superior glass-forming ability, good mechanical properties and excellent biocompatibility was discovered. The Ti-based BMG with a diameter of 7 mm can be prepared by copper mold casting and the supercooled liquid region was 52 K. Compressive strength, specific strength, Young’s modulus and microhardness of the Ti-based BMG were about 2.08 GPa, 3.2 × 10{sup 5} N m/kg, 100 GPa and 588 Hv, respectively. Electrochemical measurements indicated that the Ti-based glassy alloy possesses higher corrosion resistance than Ti–6Al–4V alloy in a simulated body fluid environment. Attachment, spreading out and proliferation of MC3T3-E1 cells on the Ti-based BMG surface demonstrated the excellent biocompatibility. Mechanisms of the formation and properties for the Ti-based glassy alloy are also discussed. The combination of high glass-forming ability, excellent mechanical properties, high corrosion resistance and good biocompatibility demonstrates the potential of the Ni-free Ti-based BMG for use in biomedical applications.

  17. Local structure of disordered Au-Cu and Au-Ag alloys

    International Nuclear Information System (INIS)

    X-ray-absorption fine structure (XAFS) and x-ray-diffraction (XRD) measurements of disordered alloys AuxCu1-x and Au0.5Ag0.5 prepared by melt spinning were performed. In the Au0.5Ag0.5 alloy, no significant local deviations of the atoms from the average fcc lattice were detected while in AuxCu1-x alloys, significant deviations of atoms from the average fcc lattice were found. Mean-square vibrations of the Cu-Cu distances revealed by the XAFS in AuxCu1-x alloys indicate the weakening of contact between Cu atoms in the dilute limit. Our computer simulation for AuxCu1-x clusters of 105 atoms reproduces the main features of both the XAFS and XRD data

  18. Changes in the microbiological and chemical characteristics of white bread during storage in paper packages modified with Ag/TiO2-SiO2, Ag/N-TiO2 or Au/TiO2.

    Science.gov (United States)

    Peter, Anca; Mihaly-Cozmuta, Leonard; Mihaly-Cozmuta, Anca; Nicula, Camelia; Ziemkowska, Wanda; Basiak, Dariusz; Danciu, Virginia; Vulpoi, Adriana; Baia, Lucian; Falup, Anca; Craciun, Grigore; Ciric, Alexandru; Begea, Mihaela; Kiss, Claudia; Vatuiu, Daniela

    2016-04-15

    Microbiological and chemical characteristics of white bread during storage in paper-packages modified with Ag/TiO2-SiO2, Ag/N-TiO2 or Au/TiO2 were investigated. The whiteness and the water retention of the modified packages were slightly superior to those exhibited by the reference sample, as the color of the composite was lighter. The water retention was very good especially for the Ag/TiO2-SiO2-paper. These improvements can be associated with the high specific surface area and with the low agglomeration tendency of Ag nanoparticles in comparison with the Au ones. The preservation activity of the composites for the bread storage is positively influenced by photoactivity and presence of nano-Ag. Packages Ag/TiO2-SiO2-paper and Ag/N-TiO2-paper can find their applicability for extending the shelf life of bread by 2 days as compared with the unmodified paper-package. No influence of the Au/TiO2 on the extending the shelf life of bread was observed. PMID:26617018

  19. Ag-Cu Bimetallic Nanoparticles Prepared by Microemulsion Method as Catalyst for Epoxidation of Styrene

    Directory of Open Access Journals (Sweden)

    Hong-Kui Wang

    2012-01-01

    Full Text Available Ag/Cu bimetallic nanocatalysts supported on reticulate-like γ-alumina were prepared by a microemulsion method using N2H4·H2O as the reducing agent. The catalysts were activated by calcination followed with hydrogen reduction at 873K, and the properties were confirmed using various characterization techniques. Compared with metal oxides particles, Ag-Cu particles exhibited smaller sizes (<5 nm after calcination in H2 at 873K. XPS results indicated that the binding energies changed with the Ag/Cu ratios, suggesting that increasing the copper content gave both metals a greater tendency to lose electrons. Furthermore, Ag-Cu bimetallic nanoparticles supported on γ-alumina showed better catalytic activity on the epoxidation of styrene as compared with the corresponding monometallic silver or copper. The styrene oxide selectivity could reach 76.6% at Ag/Cu molar ratio of 3/1, while the maximum conversion (up to 94.6% appeared at Ag/Cu molar ratio of 1/1 because of the maximum interaction between silver and copper.

  20. Hybrid Ag@TiO2 core-shell nanostructures with highly enhanced photocatalytic performance

    Science.gov (United States)

    Yang, X. H.; Fu, H. T.; Wong, K.; Jiang, X. C.; Yu, A. B.

    2013-10-01

    A new synthetic approach has been developed to prepare silver@titanium dioxide (Ag@TiO2) core-shell nanostructures with controllable size, shape, crystal phase and function at ambient conditions (e.g. in water, ≤100 ° C). This approach shows a few unique features, including short reaction time (a few minutes) for forming core-shell nanostructures, no requirement of high temperature calcinations for generating TiO2 (e.g. at ˜100 ° C in our case), tunable TiO2 shell thickness, high yield and good reproducibility. The experimental results show that the Ag@TiO2 core-shell nanostructures exhibit excellent photocatalytic activity compared to the commercial TiO2 (P25) and Ag-doped TiO2 nanocomposite in the degradation of organic dye molecules (e.g. methyl orange) with ultraviolet (UV) irradiation. This could be attributed to the large surface area of TiO2 nanoparticles for maximum harvesting of UV light, mixed anatase and rutile crystalline phases in the TiO2 shell and the effective charge separation between Ag and TiO2 that can reduce the possible recombination of electron-hole (e--h+) pairs within TiO2 generated under UV radiation. To further understand the charge separation situation within Ag-TiO2 composites, theoretical simulation (e.g. density functional theory, DFT) was employed in this study. The DFT simulation results indicate that for the Ag@TiO2 core-shell nanostructures, photo-generated electrons transfer readily from the external TiO2 layer to the internal Ag layer with heavy accumulation compared to those doping Ag on TiO2 surfaces, which may reduce the recombination of e--h+ pairs and thus enhance the photocatalytic efficiency. The findings may open a new strategy to synthesize TiO2-based photocatalysts with highly enhanced efficiency for environmental remediation applications.

  1. Bond strength optimization of Ti/Cu/Ti clad composites produced by roll-bonding

    International Nuclear Information System (INIS)

    Highlights: • Ti/Cu/Ti clad composite was successfully fabricated by the roll-bonding technique. • The most effective bonding parameter was post-annealing temperature. • The mechanism of the Cu/Ti roll bonding could be clarified using the film theory. - Abstract: This research focuses on the bond strength of the Ti/Cu/Ti composites fabricated by roll-bonding. The peel tests were used to evaluate the bond strength of the clad composites. The Taguchi technique was used to find the optimum conditions to maximize the Cu/Ti bond strength. The optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, as well as peel and microhardness tests were utilized to characterize the interfacial zones. A Taguchi L32 orthogonal array was selected to study the influence of the roll-bonding parameters, including the roller lubrication conditions, temper condition of Cu, rolling temperature, reduction in thickness, post-annealing time, and post-annealing temperature, and rolling speed on the bond strength. Based on the Taguchi statistical analysis, the rolling temperature, reduction in thickness, post-annealing temperature and rolling speed have significant effects on the bond strength. Among these, the post-annealing temperature is the most effective factor. It was shown that the selection of the highest “reduction in thickness”, the lowest “rolling speed”, and the intermediate values of “rolling temperature” and “post-annealing temperature” leads to the highest bond strength. It was also indicated that the mechanism of the Cu/Ti roll bonding could be explained using the film theory

  2. Enhancing the visible-light-induced photocatalytic activity of the self-cleaning TiO2-coated cotton by loading Ag/AgCl nanoparticles

    International Nuclear Information System (INIS)

    TiO2-coated cotton possesses excellent self-cleaning properties but requires ultraviolet irradiation for effective photocatalysis. It is highly desirable to develop self-cleaning cotton fabrics that can use visible light in high efficiency under sunlight irradiation. In this work, Ag/AgCl-TiO2-cotton was prepared by coating TiO2 films at low temperature and then loading Ag/AgCl nanoparticles via an impregnating precipitation photoreduction method. It was characterized by meanings of scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy and UV-visible diffuse reflectance spectrophotometer. In comparison with TiO2-cotton, Ag/AgCl-TiO2-cotton exhibits a highly visible-light-induced photocatalytic activity for degradation of methyl orange in water. The mechanism for the degradation of methyl orange over the Ag/AgCl-TiO2-cotton was discussed. Under visible light irradiation, Ag NPs are photoexcited due to surface plasmon resonance, and then the photoexcited electrons from Ag NPs inject into the TiO2 conduction band and the holes transfer to the surface of the AgCl particles. The produced radical groups, such as O2• −, H2O2, • OH and Cl0, can cause the photocatalytic degradation of organic pollutants. - Highlights: • TiO2 was coated on the substrates with low thermal resistance. • Ag/AgCl-TiO2-cotton shows visible-light-induced self-cleaning property. • Silver nanoparticles lead to surface plasmon resonance absorption

  3. In vitro assessment of Ag and TiO2 nanoparticles cytotoxicity

    OpenAIRE

    Apoorva Priyanka Ganapathi; Ramakrishna Devaki; Naveen Reddy Thuniki; Joydeb Manna; Bhaskar Tirumuru; Chinnapu Reddy Gopu; Sadanala Bhavya Deepthi; Rajiv Trivedi; Rohit Kumar Rana; Annie Hasan

    2014-01-01

    Background: Silver (Ag) and titanium dioxide (TiO2) nanoparticles are the most eminent nanoproducts. Due to their antimicrobial and antifungal activity, they have been the well commercialized nanosubstances. The hazards associated with human exposure to Ag and TiO2 nanoparticles should be investigated, and hence both the nanoparticles were synthesized to facilitate the risk assessment process. Methods: Prior to the cytotoxic studies, Dynamic Light Scattering (DLS) and Transmission Electr...

  4. Mechanical Properties and Electrochemical Corrosion Behavior of Al/Sn-9Zn- xAg/Cu Joints

    Science.gov (United States)

    Huang, M. L.; Huang, Y. Z.; Ma, H. T.; Zhao, J.

    2011-03-01

    The effect of Ag content on the wetting behavior of Sn-9Zn- xAg on aluminum and copper substrates during soldering, as well as the mechanical properties and electrochemical corrosion behavior of Al/Sn-9Zn- xAg/Cu solder joints, were investigated in the present work. Tiny Zn and coarsened dendritic AgZn3 regions were distributed in the Sn matrix in the bulk Sn-9Zn- xAg solders, and the amount of Zn decreased while that of AgZn3 increased with increasing Ag content. The wettability of Sn-9Zn-1.5Ag solder on Cu substrate was better than those of the other Sn-9Zn- xAg solders but worse than that of Sn-9Zn solder. The wettability of Sn-9Zn-1.5Ag on the Al substrate was also better than those of the other Sn-9Zn- xAg solders, and even better than that of Sn-9Zn solder. The Al/Sn-9Zn/Cu joint had the highest shear strength, and the shear strength of the Al/Sn-9Zn- xAg/Cu ( x = 0 wt.% to 3 wt.%) joints gradually decreased with increasing Ag content. The corrosion resistance of the Sn-9Zn- xAg solders in Al/Sn-9Zn- xAg/Cu joints in 5% NaCl solution was improved compared with that of Sn-9Zn. The corrosion potential of Sn-9Zn- xAg solders continuously increased with increasing Ag content from 0 wt.% to 2 wt.% but then decreased for Sn-9Zn-3Ag. The addition of Ag resulted in the formation of the AgZn3 phase and in a reduction of the amount of the eutectic Zn phase in the solder matrix; therefore, the corrosion resistance of the Al/Sn-9Zn- xAg/Cu joints was improved.

  5. Age-hardening and related phase transformation in an experimental Ag-Cu-Pd-Au alloy

    International Nuclear Information System (INIS)

    The age-hardening behaviour, phase transformation and related microstructural changes of an experimental Ag-Cu-Pd-Au alloy were examined by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) observations and electron probe microanalysis (EPMA). The specimen alloy showed apparent age-hardenability at the aging temperatures of 350 deg. C and 400 deg. C. By aging the solution-treated specimen at 400 deg. C, two phases of the Ag-rich α1 phase and the Pd-containing Cu-rich α2 phase were transformed into four phases of the Ag-rich α1' phase, the Cu-rich α2' phase, the CsCl-type CuPd phase and the AuCu(I) ordered phase. Microstructure of the solution-treated specimen consisted of the Ag-rich α1 matrix, Cu-rich α2 particle-like structures of various sizes and the lamellar structure of the α1 and α2 phases. When the peak hardness was obtained, the very fine lamellar structure consisting of the Ag-rich α1' and Cu-rich α2' phases was newly formed in the matrix. By further aging, the very fine lamellar structure grew and coarsened apparently, and the matrix was covered with the coarsened lamellar structure. The hardness increase was considered to be caused mainly by the diffusion and precipitation of Cu from the Ag-rich α1 matrix, and the hardness decrease in the latter stage of age-hardening process was caused by the coarsening of the very fine lamellar structure. The CsCl-type CuPd phase and the AuCu(I) ordered phase did not contribute to the hardness increase

  6. Synthesis of Ag-TiO2 composite nano thin film for antimicrobial application

    International Nuclear Information System (INIS)

    TiO2 photocatalysts have been found to kill cancer cells, bacteria and viruses under mild UV illumination, which offers numerous potential applications. On the other hand, Ag has long been proved as a good antibacterial material as well. The advantage of Ag-TiO2 nanocomposite is to expand the nanomaterial's antibacterial function to a broader range of working conditions. In this study neat TiO2 and Ag-TiO2 composite nanofilms were successfully prepared on silicon wafer via the sol-gel method by the spin-coating technique. The as-prepared composite Ag-TiO2 and TiO2 films with different silver content were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) to determine the topologies, microstructures and chemical compositions, respectively. It was found that the silver nanoparticles were uniformly distributed and strongly attached to the mesoporous TiO2 matrix. The morphology of the composite film could be controlled by simply tuning the molar ratio of the silver nitrate aqueous solution. XPS results confirmed that the Ag was in the Ag0 state. The antimicrobial effect of the synthesized nanofilms was carried out against gram-negative bacteria (Escherichia coli ATCC 29425) by using an 8 W UV lamp with a constant relative intensity of 0.6 mW cm-2 and in the dark respectively. The synthesized Ag-TiO2 thin films showed enhanced bactericidal activities compared to the neat TiO2 nanofilm both in the dark and under UV illumination.

  7. Effect of Synthesis Techniques on Crystallization and Optical Properties of Ag-Cu Bimetallic Nanoparticles

    Science.gov (United States)

    Xiong, Ziye; Qin, Fen; Huang, Po-Shun; Nettleship, Ian; Lee, Jung-Kun

    2016-04-01

    Silver (Ag)-copper (Cu) bimetallic nanoparticles (NPs) were synthesized by the reduction of silver nitrate and copper (II) acetate monohydrate using ethylene glycol in a microwave (MW) heating system with controlled reaction times ranging from 5 min to 30 min. The molar ratio Ag/Cu was varied from 1:1 to 1:3. The effect of reaction conditions on the bimetallic NPs structures and compositions were characterized by x-ray photoelectron spectroscopy, x-ray diffraction and transmission electron microscopy. The average particle size was approximately 150 nm. The surface plasmon resonance (SPR) of Ag-Cu bimetallic NPs was investigated by monitoring the SPR band peak behavior via UV/Vis spectrophotometry. The resonance peak positions and peak widths varied due to the different structures of the bimetallic NPs created under the synthesis conditions. In the MW heating method, the reduction of Cu was increased and Cu was inhomogeneously deposited over the Ag cores. As the composition of Cu becoming higher in the Ag-Cu bimetallic NPs, the absorption between 400 nm to 600 nm was greatly enhanced.

  8. Superhydrophobic surfaces via electroless displacement of nanometric Cu layers by Ag{sup +}

    Energy Technology Data Exchange (ETDEWEB)

    Brenier, R., E-mail: roger.brenier@lpmcn.univ-lyon1.fr [Universite de Lyon, Universite Lyon1, Laboratoire PMCN, CNRS, UMR 5586, F69622 Villeurbanne Cedex (France); Ramos, S.M.M.; Montchanin, M. [Universite de Lyon, Universite Lyon1, Laboratoire PMCN, CNRS, UMR 5586, F69622 Villeurbanne Cedex (France)

    2009-05-30

    This paper explores the possibility of making hydrophobic and superhydrophobic surfaces from electroless displacement of Cu by Ag{sup +}, in the case where Cu oxidation is limited owing to Cu layers of nanometric thicknesses. The morphology of the Ag layers is studied by scanning electron microscopy for Cu thicknesses between 10 and 80 nm. The mapping of the elemental content of the layers by electron dispersive X-ray analysis also has been used to clarify the particle growing by diffusion limited aggregation. It is shown that the average size and the shape complexity of the Ag particles increase with the Cu thickness. The addition of dimethyl sulfoxide in the Ag{sup +} aqueous solution improves the surface homogeneity, increases the particle density and decreases their sizes. The wetting behaviour of the surfaces, after grafting with octadecanethiol, has been studied from measurements of the contact angles of a drop of water. According to the thickness of the initial Cu layer and the morphology of the Ag layer, contact angles range between 110{sup o} and 154{sup o}. Superhydrophobic surfaces are obtained from 80 nm thick Cu layers.

  9. A highly sensitive ethanol sensor based on Ag@TiO2 nanoparticles at room temperature

    International Nuclear Information System (INIS)

    Highlights: • Novel core–shell Ag@TiO2 nanoparticles composite material was prepared for ethanol sensor. • The sensor exhibits low detection limit (0.15 ppm). • High selectivity for other volatile gases. - Abstract: In this study, the ethanol-sensing characteristics of Ag@TiO2 nanoparticles were investigated. The morphology, structure, and formation mechanism of the Ag@TiO2 core–shell nanoparticles were carefully studied using X-ray diffraction, transmission electron microscopy, ultraviolet–visible spectroscopy, ZetaSizer Nano ZS and energy-dispersive X-ray spectroscopy. A gas sensing study showed that Ag@TiO2 is a promising sensor for detecting ethanol gas at low concentrations (below 5 ppm) at room working temperature. Ag@TiO2 exhibited a sensor response of 1.04–4.35 at the ethanol concentration from 0.15 ppm to 5 ppm. In addition, the sensor presented an excellent selectivity and stability for ethanol gas. This systematic study of the promising ethanol-sensing characteristics of Ag@TiO2 nanoparticles can facilitate the development of sensors that detect ethanol gas

  10. Synthesis and anti-bacterial activity of Cu, Ag and Cu-Ag alloy nanoparticles: A green approach

    International Nuclear Information System (INIS)

    Research highlights: → Synthesis of novel nanosized copper-silver alloys of different compositions. → Completely green approach for synthesis of water soluble bimetallic nanoparticle. → Interesting anti-bacterial activity of as synthesized metal and alloy nanoparticle. -- Abstract: Metallic and bimetallic nanoparticles of copper and silver in various proportions were prepared by microwave assisted chemical reduction in aqueous medium using the biopolymer, starch as a stabilizing agent. Ascorbic acid was used as the reducing agent. The silver and copper nanoparticles exhibited surface plasmon absorption resonance maxima (SPR) at 416 and 584 nm, respectively; while SPR for the Cu-Ag alloys appeared in between depending on the alloy composition. The SPR maxima for bimetallic nanoparticles changes linearly with increasing copper content in the alloy. Transmission electron micrograph (TEM) showed monodispersed particles in the range of 20 ± 5 nm size. Both silver and copper nanoparticles exhibited emission band at 485 and 645 nm, respectively. The starch-stabilized nanoparticles exhibited interesting antibacterial activity with both gram positive and gram negative bacteria at micromolar concentrations.

  11. Atmospheric Corrosion of Ag and Cu with Ozone, UV and NaCl

    Science.gov (United States)

    Lin, Huang

    Ag and Cu are both used for electronics and are susceptible to atmospheric corrosion. They are also good corrosivity monitors used to evaluate aggressiveness of the environment. Unfortunately, laboratory exposure testing does not always represent field environments very well. Discrepancies between lab and field exposure tests are not uncommon. For example, Ag does not corrode in salt spray exposure during ASTM B117 test, while it corrodes everywhere outdoor. This suggests that new laboratory exposure test for Ag needs to be designed and studied. A full factorial experiment was carried out with three factors: ozone, UV intensity and relative humidity (RH). NaCl was loaded by fast evaporation of NaCl/ethanol solution before exposure. After exposure, corrosion products were identified by XRD and quantified by galvanostatic reduction technique. For lab exposure samples, AgCl was identified as the only corrosion product in high RH (87%) environments, while Ag2O and AgO formed as well during exposures at low RH. This result derived a qualitative prediction on corrosion behavior of Ag in field. It predicts that less stable silver compounds such as oxide and sulfate are possible corrosion products in field even silver chloride is the dominant corrosion product forming in field. This prediction was confirmed by analysis of field exposed Ag samples. By quantification of corrosion products, it is determined that UV has two contravening effects on atmospheric corrosion of Ag: photolysis of ozone to generate stronger oxidizing species such as atomic O and photodecomposition of Ag corrosion products by UV radiation. Following its success in Ag corrosion research, the environment of UV, ozone and NaCl was extended to study Cu corrosion. It is determined that UV alone can double Cu corrosion rate by generation of electron-hole pairs in n-type cuprous oxide. It is also found that ozone alone is not as aggressive on Ag as on Cu because protection of naturally formed cuprous oxide

  12. Effect of the Vibrational Modes on the Ag-Cu Phase Diagram

    Institute of Scientific and Technical Information of China (English)

    DUAN Su-Qing; ZHAO Xian-Geng; LIU Shao-Jun; MA Ben-Kun

    2000-01-01

    We calculated the vibrational free energies of the selected ordered compounds in the Ag-Cu system by using two kinds of methods: (1) calculating the phonon dispersion and density of states and the consequently vibrational free energies by using the method of ab initio inverted interatomic potentials and dynamic matrix; (2) the vibrational free energies determined by a Debye-Griineisen approximation. The Ag-Cu phase diagram is calculated by the cluster variation method. The results show that the solubility at Ag-rich end of the calculated phase diagram considering vibrational modes by using the first method is in better agreement with the experimental.

  13. A novel TiO2 nanofiber supported PdAg catalyst for methanol electro-oxidation

    International Nuclear Information System (INIS)

    A novel PdAg/TiO2 nanofiber electrocatalyst for methanol oxidation was fabricated by using TiO2 nanofiber as support. The structural and electrochemical properties of the PdAg/TiO2 nanofiber catalyst were characterized by XRD (X-ray diffraction), TEM (the transmission electron microscopy) and electrochemical analysis. The experiment results showed that the large surface area and porous structure of TiO2 nanofiber were preferable to the dispersion of nanosized PdAg alloy on the surface of TiO2 nanofiber support. The electrocatalytic activity for methanol oxidation of the PdAg/TiO2 nanofiber catalyst has shown promising electrocatalytic and anti-poisoning capabilities. The methanol oxidation mechanism of the PdAg/TiO2 nanofiber catalyst was mainly resulted from the photocatalytic function of the composite TiO2 material that had high catalytic activity without UV light illumination. The PdAg/TiO2 catalyst might become a promising candidate for direct methanol fuel cell. - Highlights: • Novel non-Pt catalyst of PdAg/TiO2 nanofiber for methanol oxidation is fabricated. • PdAg alloy is dispersed uniformly on the surface of TiO2 nanofiber support. • The novel catalyst shows promising electrocatalytic activity and anti-poisoning ability. • The methanol oxidation mechanism of the catalyst results from photocatalytic mechanism of TiO2

  14. Thermopower of YBa2Cu3O7-δ-Ag composites

    International Nuclear Information System (INIS)

    This paper reports on the percolation behavior of normal-state thermopower, resistivity, and superconductivity that have been studied in YBa2Cu3O7-δ-Ag (YBCO-Ag) composite systems. The normal-state resistivity and thermopower show a percolation threshold at a Ag volume fraction (VAg) of 20% to 30%, whereas the superconducting network shows a threshold at a VAg of ∼70% to 80%. The results obtained from this study show that the YBCO-Ag composite obtained from Ag2O and YBCO powders is uniformly distributed with Ag and YBCO remaining as separate phases without changing their characteristics. The measurements of thermopower indicate that the normal-state thermopower and phonon-drag thermopower are affected by the Ag addition. The stability of YBCO is increased when it is in composite form

  15. Fabrication of a novel visible-light-driven photocatalyst Ag-AgI-TiO{sub 2} nanoparticles supported on carbon nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Dandan; Bai, Jie, E-mail: baijie@imut.edu.cn; Liang, Haiou; Wang, Junzhong; Li, Chunping

    2015-09-15

    Graphical abstract: - Highlights: • Visible-light-induced Ag-AgI-TiO{sub 2}/CNFs nanocomposites had been successfully prepared. • Ag-AgI-TiO{sub 2}/CNFs could be easily separated and recycled from an aqueous solution. • The application of CNFs acting as supporters made the photocatalysts have high adsorption capacity. • Ag-AgI-TiO{sub 2}/CNFs could efficiently degrade different organic dyes. - Abstract: Novel visible-light-driven photocatalysts Ag-AgI-TiO{sub 2} nanoparticles embedded onto carbon nanofibers were successfully prepared. Electrospinning technology followed by high-temperature calcination was adopted for the fabrication of carbon nanofibers (CNFs) acting as a supporter. Ag-TiO{sub 2}/CNFs nanocomposites were prepared by combining in situ reduction with physical adsorption process. Ag-AgI-TiO{sub 2}/CNFs were synthesized by oxidizing some silver nanoparticles (Ag NPs) contained in Ag-TiO{sub 2}/CNFs to silver iodine (AgI) via chemical oxidation method using iodine (I{sub 2}) as oxidation agents. The as-prepared nanocomposites were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectra (DRS), and Fourier transform infrared spectroscopy (FTIR). The as-fabricated Ag-AgI-TiO{sub 2}/CNFs showed high efficient adsorption and photocatalytic activity for decomposition of methyl orange (MO), acid red 18 (AR18), methylene blue (MB), and fluorescence sodium under visible light irradiation, which were attributed to the synergistic effects between the high adsorption capacity, good conductivity of carbon nanofibers, and the extraordinary plasma effect of Ag-AgI nanoparticles. In addition, the as-prepared composites could be easily separated from the solution phase due to the large length–diameter ratio of CNFs. The mechanism for the enhanced photocatalytic activity concerned with Ag-AgI-TiO{sub 2}/CNFs was proposed.

  16. Hybrid Ag@TiO2 core–shell nanostructures with highly enhanced photocatalytic performance

    International Nuclear Information System (INIS)

    A new synthetic approach has been developed to prepare silver@titanium dioxide (Ag@TiO2) core–shell nanostructures with controllable size, shape, crystal phase and function at ambient conditions (e.g. in water, ≤100 ° C). This approach shows a few unique features, including short reaction time (a few minutes) for forming core–shell nanostructures, no requirement of high temperature calcinations for generating TiO2 (e.g. at ∼100 ° C in our case), tunable TiO2 shell thickness, high yield and good reproducibility. The experimental results show that the Ag@TiO2 core–shell nanostructures exhibit excellent photocatalytic activity compared to the commercial TiO2 (P25) and Ag-doped TiO2 nanocomposite in the degradation of organic dye molecules (e.g. methyl orange) with ultraviolet (UV) irradiation. This could be attributed to the large surface area of TiO2 nanoparticles for maximum harvesting of UV light, mixed anatase and rutile crystalline phases in the TiO2 shell and the effective charge separation between Ag and TiO2 that can reduce the possible recombination of electron–hole (e−–h+) pairs within TiO2 generated under UV radiation. To further understand the charge separation situation within Ag–TiO2 composites, theoretical simulation (e.g. density functional theory, DFT) was employed in this study. The DFT simulation results indicate that for the Ag@TiO2 core–shell nanostructures, photo-generated electrons transfer readily from the external TiO2 layer to the internal Ag layer with heavy accumulation compared to those doping Ag on TiO2 surfaces, which may reduce the recombination of e−–h+ pairs and thus enhance the photocatalytic efficiency. The findings may open a new strategy to synthesize TiO2-based photocatalysts with highly enhanced efficiency for environmental remediation applications. (paper)

  17. Preparation and Photocatalytic Activity of Ag Modified Ti-Doped-Bi2O3 Photocatalyst

    Directory of Open Access Journals (Sweden)

    Lilan Zhang

    2014-01-01

    Full Text Available Ti doped Bi2O3 (TDB and Ag ion modified Ti doped Bi2O3 (Ag@TDB photocatalysts were prepared by framework replacement synthesis method with different Ag loadings (0.05, 0.3, 0.75, and 1.0 mol/L AgNO3. The structural properties of the prepared catalysts were studied by scanning electron microscope (SEM, X-ray diffraction (XRD, BET surface area, and UV/Vis diffuse reflectance (DRS. The XRD spectra of the Ti doped Bi2O3 calcined at 650°C showed the diffraction peaks of a mixture of Bi12TiO20 and Bi4Ti3O12, with bits of mixed crystallite consisting of TiO2 and B2O3. A high blue shift in the range 650–550 nm was detected in the DRS band. This blue shift increased with the decreasing Ag content. The photocatalytic activities of the catalysts were evaluated for the degradation of crystal violet (CV under UV light irradiation. The results indicated that the degradation rate of CV by using 1.0 mol/L AgNO3 doped bismuth titanate composite photocatalyst (1.0 Ag@TDB was 1.9 times higher than that by using the bare Ti doped Bi2O3 photocatalyst. The higher activity of Ag@TDB is due to the enhancement of electron-hole pair separation by the electron trapping of silver particles.

  18. Electrochemical and structural characterization of nanocomposite Agy:TiNx thin films for dry bioelectrodes: the effect of the N/Ti ratio and Ag content

    International Nuclear Information System (INIS)

    Highlights: • Agy:TiNx thin films were sputtered with different N/Ti atomic ratios and Ag contents. • The electroactive area increases (1000-fold) with increasing N/Ti atomic ratios. • The films display impedances <10 kΩ at the 1–50 Hz interval (EEG range). • No Ag surface segregation was visible in the under-stoichiometric samples. • The samples with N/Ti atomic ratio = 0.3 (15 at.% Ag) and 0.7 (32 at.% Ag) are the most appropriate for bioelectrode applications. - ABSTRACT: Agy:TiNx nanocomposite thin films sputtered with different N/Ti atomic ratios and Ag atomic contents were characterized from the structural and morphological points of view. Their electrochemical behaviour was studied in a synthetic sweat solution, aiming at selecting a suitable material for biolectrode applications. An increase of the N/Ti atomic ratio, which is accompanied by an increase of the Ag atomic content, leads to a substantial increase of the roughness and porosity of the samples, especially for N/Ti ratios >0.2. For N/Ti atomic ratios up to 0.3 (15 at.% Ag) no metallic Ag segregation is visible in the TiNx matrix. Hence, the possible formation of TiAg and Ti2Ag intermetallics or even a Ag/TiAg/Ti2Ag phase mixture, although not demonstrated, should not be disregarded. As for the N/Ti atomic ratio = 0.7 (32 at.% Ag) sample, the Ag phases are predominantly concentrated near the interface with the substrate. The amount of Ag phases at the surface of the films remains somewhat low for all TiN under-stoichiometric films, even for Ag atomic contents up to 32 at.%. When the TiNx matrix reaches the stoichiometric condition (sample with N/Ti atomic ratio = 1 and 20 at.% Ag), Ag segregation occurs and metallic Ag aggregates are visible at the surface of the film, leading to a substantially different electrochemical behaviour. The impedance of the Agy:TiNx films in synthetic sweat solution is mainly ruled by the roughness/porosity variation, thus the higher the N/Ti atomic ratio

  19. Experiment study on Be|Ti/Cu|CuCrZr joints by hot isostatic pressing bonding

    International Nuclear Information System (INIS)

    Performances of Be/Cu joints fabricated by hot isostatic pressing (HIP) bonding were studied by means of various test Methods, such as shearing test, scanning electron microscopy(SEM) observation, energy dispersion spectrometer(EDS) and X-ray Diffraction(XRD) analysis, when Ti (PVD-coated on Be)/Cu (PVD-coated on CuCrZr) interlayers were used. This study considered several diffusion surface treatments (such as chemical etching, polishing, etc.) for minimizing or eliminating the effects of the oxide film on beryllium to promote good diffusion bond between these materials. Experiments indicated that the joints HIPed at 580 degree C/145 MPa/2 h showed high shearing strength (up to 123 MPa) at room temperature and no defect such as cracks was observed at the bonding interface dut to the role of the etching with a dilute acid solution to remove native oxide films on beryllium surface prior to titanium coating. The strength moderately decreased when the diffusion holding time increased from 2 h to 4 h. The thin titanium diffusion barrier (∼10μm) which was coated on the beryllium surface have prevented the reaction between Be and Cu, but CuTi phase was formed at Ti/Cu interface. It is considered the phase limited the bonding strength to higher level. (authors)

  20. Enhanced resistive switching effect in Ag nanoparticle embedded BaTiO3 thin films

    International Nuclear Information System (INIS)

    Ag nanoparticle (NP) embedded BaTiO3 (BTO) thin films on SrRuO3-coated SrTiO3 (STO) substrates are prepared by the integrated nanocluster beam deposition and laser-molecular beam epitaxy. Enhanced resistive switching, up to an ON/OFF ration of 104, has been achieved at low switching voltage (less than 1 V) without a forming voltage. These characteristics make such nanocomposite film very promising for application of low voltage non-volatile random access memory. The enhanced resistive switching effect may be attributed to the charge storage effect of the Ag nanoparticles and easy formation of Ag filament inside the BTO film

  1. Kinetic trapping through coalescence and the formation of patterned Ag-Cu nanoparticles

    Science.gov (United States)

    Grammatikopoulos, Panagiotis; Kioseoglou, Joseph; Galea, Antony; Vernieres, Jerome; Benelmekki, Maria; Diaz, Rosa E.; Sowwan, Mukhles

    2016-05-01

    In recent years, due to its inherent flexibility, magnetron-sputtering has been widely used to synthesise bi-metallic nanoparticles (NPs) via subsequent inert-gas cooling and gas-phase condensation of the sputtered atomic vapour. Utilising two separate sputter targets allows for good control over composition. Simultaneously, it involves fast kinetics and non-equilibrium processes, which can trap the nascent NPs into metastable configurations. In this study, we observed such configurations in immiscible, bi-metallic Ag-Cu NPs by scanning transmission electron microscopy (S/TEM) and electron energy-loss spectroscopy (EELS), and noticed a marked difference in the shape of NPs belonging to Ag- and Cu-rich samples. We explained the formation of Janus or Ag@Cu core/shell metastable structures on the grounds of in-flight mixed NP coalescence. We utilised molecular dynamics (MD) and Monte Carlo (MC) computer simulations to demonstrate that such configurations cannot occur as a result of nanoalloy segregation. Instead, sintering at relatively low temperatures can give rise to metastable structures, which eventually can be stabilised by subsequent quenching. Furthermore, we compared the heteroepitaxial diffusivities along various surfaces of both Ag and Cu NPs, and emphasised the differences between the sintering mechanisms of Ag- and Cu-rich NP compositions: small Cu NPs deform as coherent objects on large Ag NPs, whereas small Ag NPs dissolve into large Cu NPs, with their atoms diffusing along specific directions. Taking advantage of this observation, we propose controlled NP coalescence as a method to engineer mixed NPs of a unique, patterned core@partial-shell structure, which we refer to as a ``glass-float'' (ukidama) structure.In recent years, due to its inherent flexibility, magnetron-sputtering has been widely used to synthesise bi-metallic nanoparticles (NPs) via subsequent inert-gas cooling and gas-phase condensation of the sputtered atomic vapour. Utilising two

  2. Novel PdAgCu ternary alloy: Hydrogen permeation and surface properties

    Science.gov (United States)

    Tarditi, Ana M.; Braun, Fernando; Cornaglia, Laura M.

    2011-05-01

    Dense PdAgCu ternary alloy composite membranes were synthesized by the sequential electroless plating of Pd, Ag and Cu on top of both disk and tubular porous stainless steel substrates. X-ray diffraction and scanning electron microscopy were employed to study the structure and morphology of the tested samples. The hydrogen permeation performance of these membranes was investigated over a 350-450 °C temperature range and a trans-membrane pressure up to 100 kPa. After annealing at 500 °C in hydrogen stream followed by permeation experiments, the alloy layer presented a FCC crystalline phase with a bulk concentration of 68% Pd, 7% Ag and 25% Cu as revealed by EDS. The PdAgCu tubular membrane was found to be stable during more than 300 h on hydrogen stream. The permeabilities of the PdAgCu ternary alloy samples were higher than the permeabilities of the PdCu alloy membranes with a FCC phase. The co-segregation of silver and copper to the membrane surface was observed after hydrogen permeation experiments at high temperature as determined by XPS.

  3. Novel PdAgCu ternary alloy: Hydrogen permeation and surface properties

    International Nuclear Information System (INIS)

    Dense PdAgCu ternary alloy composite membranes were synthesized by the sequential electroless plating of Pd, Ag and Cu on top of both disk and tubular porous stainless steel substrates. X-ray diffraction and scanning electron microscopy were employed to study the structure and morphology of the tested samples. The hydrogen permeation performance of these membranes was investigated over a 350-450 deg. C temperature range and a trans-membrane pressure up to 100 kPa. After annealing at 500 deg. C in hydrogen stream followed by permeation experiments, the alloy layer presented a FCC crystalline phase with a bulk concentration of 68% Pd, 7% Ag and 25% Cu as revealed by EDS. The PdAgCu tubular membrane was found to be stable during more than 300 h on hydrogen stream. The permeabilities of the PdAgCu ternary alloy samples were higher than the permeabilities of the PdCu alloy membranes with a FCC phase. The co-segregation of silver and copper to the membrane surface was observed after hydrogen permeation experiments at high temperature as determined by XPS.

  4. Novel PdAgCu ternary alloy: Hydrogen permeation and surface properties

    Energy Technology Data Exchange (ETDEWEB)

    Tarditi, Ana M.; Braun, Fernando [Instituto de Investigaciones en Catalisis y Petroquimica (FIQ, UNL-CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina); Cornaglia, Laura M., E-mail: lmcornag@fiq.unl.edu.ar [Instituto de Investigaciones en Catalisis y Petroquimica (FIQ, UNL-CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina)

    2011-05-15

    Dense PdAgCu ternary alloy composite membranes were synthesized by the sequential electroless plating of Pd, Ag and Cu on top of both disk and tubular porous stainless steel substrates. X-ray diffraction and scanning electron microscopy were employed to study the structure and morphology of the tested samples. The hydrogen permeation performance of these membranes was investigated over a 350-450 deg. C temperature range and a trans-membrane pressure up to 100 kPa. After annealing at 500 deg. C in hydrogen stream followed by permeation experiments, the alloy layer presented a FCC crystalline phase with a bulk concentration of 68% Pd, 7% Ag and 25% Cu as revealed by EDS. The PdAgCu tubular membrane was found to be stable during more than 300 h on hydrogen stream. The permeabilities of the PdAgCu ternary alloy samples were higher than the permeabilities of the PdCu alloy membranes with a FCC phase. The co-segregation of silver and copper to the membrane surface was observed after hydrogen permeation experiments at high temperature as determined by XPS.

  5. CuO and Ag2O effect on electrical properties of barium vanadate glasses

    International Nuclear Information System (INIS)

    Effect of CuO on barium vanadate glass (BVG) conductivity on direct and alternating currents in the frequency range (102-104)Hz has been studied. Effect of Ag2O has been also studied for comparison, as Ag and Cu have idendical structure of external electron shells (d10, S1). CuO introduction to binary barium vanadate glasses as a modificator results in the conductivity improvement on direct and alternating currents conditioned with reducing activation energy of small radius polaron jump, apparently, owing to exchange (ferromagnetic) interaction between V(IV) and Cu(II). Jump activation energy in barium vanadate glasses with Ag2O increases and conductivity drops due to the distance increase between vanadium atoms

  6. High-temperature thermal expansion and structural behaviour of stromeyerite, AgCuS

    International Nuclear Information System (INIS)

    Results of simultaneous thermal analysis, synchrotron and neutron powder diffraction in the range from room temperature up to the melting point at 936 K on non-superionic orthorhombic β-AgCuS as well as on superionic hexagonal α- and cubic δ-AgCuS are reported. On heating the sample is only stable in argon. The following phase transitions occur in AgCuS at elevated temperatures: β361K → α399K →α+δ 439K→δ. The volume changes at the superionic β→α and α→δ phase transitions are about 2.3 and 0.6%. The volume thermal expansion coefficients are 26 x 10-6, 130 x 10-6 and 85 x 10-6 K-1 for the pure β-, α- and δ-phases, respectively. Models for the average structures of α- and δ-AgCuS are proposed and discussed. Ionic conductivity in δ-AgCuS may originate from cation jumps in 'skewed' directions between nearest-neighbour tetrahedral sites via the peripheries of the octahedral cavities. A correlation between the temperature dependence of the cation redistribution in δ-AgCuS and the temperature dependence of the ionic conductivity is assumed. A two-dimensional nature of the ionic conductivity due to cation jumps in slabs perpendicular to the c-direction is supposed for α-AgCuS. There is no evidence for ionic diffusion through the (1/2, 1/2, 1/2) site in directions in either superionic α- or δ-phases

  7. Kinetic trapping through coalescence and the formation of patterned Ag-Cu nanoparticles.

    Science.gov (United States)

    Grammatikopoulos, Panagiotis; Kioseoglou, Joseph; Galea, Antony; Vernieres, Jerome; Benelmekki, Maria; Diaz, Rosa E; Sowwan, Mukhles

    2016-05-14

    In recent years, due to its inherent flexibility, magnetron-sputtering has been widely used to synthesise bi-metallic nanoparticles (NPs) via subsequent inert-gas cooling and gas-phase condensation of the sputtered atomic vapour. Utilising two separate sputter targets allows for good control over composition. Simultaneously, it involves fast kinetics and non-equilibrium processes, which can trap the nascent NPs into metastable configurations. In this study, we observed such configurations in immiscible, bi-metallic Ag-Cu NPs by scanning transmission electron microscopy (S/TEM) and electron energy-loss spectroscopy (EELS), and noticed a marked difference in the shape of NPs belonging to Ag- and Cu-rich samples. We explained the formation of Janus or Ag@Cu core/shell metastable structures on the grounds of in-flight mixed NP coalescence. We utilised molecular dynamics (MD) and Monte Carlo (MC) computer simulations to demonstrate that such configurations cannot occur as a result of nanoalloy segregation. Instead, sintering at relatively low temperatures can give rise to metastable structures, which eventually can be stabilised by subsequent quenching. Furthermore, we compared the heteroepitaxial diffusivities along various surfaces of both Ag and Cu NPs, and emphasised the differences between the sintering mechanisms of Ag- and Cu-rich NP compositions: small Cu NPs deform as coherent objects on large Ag NPs, whereas small Ag NPs dissolve into large Cu NPs, with their atoms diffusing along specific directions. Taking advantage of this observation, we propose controlled NP coalescence as a method to engineer mixed NPs of a unique, patterned core@partial-shell structure, which we refer to as a "glass-float" (ukidama) structure. PMID:27119383

  8. Fabrication and Characterization of Porous Sintered Ti-Ag Compacts for Biomedical Application Purpose

    Institute of Scientific and Technical Information of China (English)

    Legan Hou; Li Li; Yufeng Zheng

    2013-01-01

    Porous sintered Ti-Ag compacts with different Ag content were fabricated by powder metallurgy.The associated hydrothermal treatment and the effect on the apatite formation were studied.The results suggested that TiO was generated under the condition of low vacuum (1 × 10-2 Pa) during the process of burning out the spacer-holding particles.After hydrothermal treatment,a sub-microscale porous layer was formed at the pore wall surface of the samples.The apatite-inducing ability of hydrothermal treated porous sintered Ti-Ag compacts with different Ag content was evaluated in modified simulated body fluid (SBF).And the results proved that there is a clear correlation between the apatite-inducing ability and Ag content.The higher Ag content in porous leads to the decrease of Na+ ions and basic hydroxyl (OH)b amount,resulting in the decline of apatite-inducing ability in the first stage.However,their apatite-inducing ability was not significantly different from that of Ti after two weeks SBF immersing.Hence,the ionic activity should restore with the processing of SBF soaking,as the saturation of Ag effect.

  9. Thermal efficiencies of NiTiCu shape memory alloys

    International Nuclear Information System (INIS)

    Thermal efficiencies were calculated based on an ideal shape-memory-effect heat-engine cycle. It was found that the addition of copper in the NiTi shape-memory alloy provides an important increase of the thermal efficiency with the highest temperature transformation range. Thermal efficiency values obtained range from 4.7 to 5.3% and Carnot efficiencies were around 25%. These efficiencies have been evaluated by means of calorimetric techniques and mechanical tests for five NiTiCu shape-memory alloys. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  10. Distribution of Ag in Cu-sulfides in Kupferschiefer deposit, SW Poland

    Science.gov (United States)

    Kozub, Gabriela A.

    2014-05-01

    The Cu-Ag Kupferschiefer deposit located at the Fore-Sudetic Monocline (SW Poland) is a world class deposit of stratabound type. The Cu-Ag mineralization in the deposit occurs in the Permian sedimentary rocks (Rotliegend and Zechstein) in three lithological types of ore: the dolomite, the black shale and the sandstone. Silver, next to copper, is the most important element in the Kupferschiefer deposit (Salamon 1979; Piestrzyński 2007; Pieczonka 2011). Although occurrence of the Ag-minerals such as native silver, silver amalgams, stromeyerite, jalpaite and mckinstryite, silver is mainly present in the deposit due to isomorphic substitutions in Cu-minerals such as chalcocite, bornite, tennantite, covellite and chalcopyrite. The aim of the study was to define distribution of silver in Cu-minerals and correlate occurrence of Ag-enriched Cu-sulfides with native silver and silver amalgams. Identification of minerals and textural observation were performed using field emission scanning electron microscope. Analyzes of chemical composition of Cu-sulfides were performed utilizing electron microprobe. Silver concentration in Cu sulfides ranges from 0.1 to 10.4 wt.% in chalcocite, 0.2-15.8 wt.% in bornite, 0.1-2.9 wt.% in tennantite, 0.05-0.3 wt.% in chalcopyrite and ca. 0.4 wt.% in covellite. In general, distribution of silver in Cu-minerals is irregular, as indicated by high variations of Ag concentration in each mineral. Content of Ag in Cu-sulphides, in samples where native silver and silver amalgams are not found, is lower than in samples, where native silver and silver amalgams are noted. The chemical analyzes of Ag-bearing Cu-minerals indicate decrease of Cu content in minerals with high Ag concentration. In such case, decrease of Fe content is also noted in bornite. Lack of micro-inclusions of the native silver or silver amalgams in the Cu-minerals indicates that presence of Ag is mainly related to the isomorphic substitutions. This is in agreement with previous

  11. Different interdiffusion characteristics between {Ag}/{YBa2Cu3O7-x} and {Al}/{YBa2Cu3O7-x} contact interfaces

    Science.gov (United States)

    Kang Jinfeng; Chen Xin; Wang Youxiang; Han Ruqi; Xiong Guangcheng; Lian Guijun; Li Jie; Wu Sicheng

    1995-04-01

    The differences between the interdiffusion characteristics of {Ag}/{YBa2Cu3O7-x} and {Al}/{YBa2Cu3O7-x} contact interfaces have been revealed by secondary ion mass spectrometry (SIMS). The different electrical properties of {Ag}/{YBa2Cu3O7-x} and YBa 2Cu 3O 7-x films after high temperature treatment are well understood by the SIMS results.

  12. Study of thermal annealing induced plasmonic bleaching in Ag:TiO2 nanocomposite thin films

    International Nuclear Information System (INIS)

    Graphical abstract: The plasmonic bleaching observed in Ag:TiO2 nanocomposite thin films, when annealed at 450 °C in Ar environment, is due to the dissociation of Ag nanoparticles followed by diffusion of Ag atoms outside the nanocomposite film and into substrate. - Plasmonic properties of metal nanomaterials critically affect on thermal treatments. One of such effects is ‘plasmonic-bleaching’ observed in ‘atom beam co-sputtering’ derived Ag:TiO2 nanocomposite thin films, when annealed at 450 °C. The origin of bleaching is investigated using glancing angle X-ray diffraction and Rutherford backscattering spectroscopy. The kinetics of Ag nanoparticles during the deposition and after thermal treatment is presented to understand involved host-matrix interactions. Based on Rutherford Materials Program simulation, possible mechanism of bleaching is presented

  13. Enhanced photocatalysis by coupling of anatase TiO2 film to triangular Ag nanoparticle island.

    Science.gov (United States)

    Xu, Jinxia; Xiao, Xiangheng; Ren, Feng; Wu, Wei; Dai, Zhigao; Cai, Guangxu; Zhang, Shaofeng; Zhou, Juan; Mei, Fei; Jiang, Changzhong

    2012-01-01

    In order to overcome the low utilization ratio of solar light and high electron-hole pair recombination rate of TiO2, the triangular Ag nanoparticle island is covered on the surface of the TiO2 thin film. Enhancement of the photocatalytic activity of the Ag/TiO2 nanocomposite system is observed. The increase of electron-hole pair generation is caused by the enhanced near-field amplitudes of localized surface plasmon of the Ag nanoparticles. The efficiently suppressed recombination of electron-hole pair caused by the metal-semiconductor contact can also enhance the photocatalytic activity of the TiO2 film. PMID:22548875

  14. Antibacterial and corrosion resistance of TiN/Ag multilayers by ion beam assisted deposition

    International Nuclear Information System (INIS)

    TiN/Ag multilayers were deposited on medical stainless steel 317L by ion beam assisted deposition (IBAD). Standard agar dilution method was used to test antibacterial ratio using E.coil and S.aureus. Electro-chemical method was used to test corrosion resistance of the film in Hank's simulated human plasma. The structure and depth profile of the elements were investigated by XPS, XRD and ALES. The results show that a strong antibacterial ratio (>99%) can be obtained when the modulation period of TiN/Ag multilayers is 8 nm (5 nm TiN and 3 nm Ag). Its corrosion resistance is better than medical stainless steel 317L, approaching monolayer TiN. (authors)

  15. Ti{sub 1−x}Ag{sub x} electrodes deposited on polymer based sensors

    Energy Technology Data Exchange (ETDEWEB)

    Marques, S.M., E-mail: mariana.marques@fisica.uminho.pt [GRF-CFUM, Physics Department, University of Minho, 4800-058 Guimarães (Portugal); Manninen, N.K. [SEG-CEMUC Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); Ferdov, Stanislav [GRF-CFUM, Physics Department, University of Minho, 4800-058 Guimarães (Portugal); Lanceros-Mendez, S. [Physics Department, University of Minho, 4700-057 Braga (Portugal); Carvalho, S. [GRF-CFUM, Physics Department, University of Minho, 4800-058 Guimarães (Portugal); SEG-CEMUC Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal)

    2014-10-30

    Graphical abstract: - Highlights: • Ti{sub 1−x}Ag{sub x} thin films with diverse Ag/Ti ratios were deposited by sputtering on piezoelectric PVDF. • The deposition conditions do not promote changes on the polymer structure. • The coatings do not change the piezoelectric properties of the polymer. • Sheet resistivity values show a typical behavior of a binary alloy system. • The deposited films are suitable for the development of functional electrodes. - Abstract: Piezoelectric materials are interesting for the development of sensors and actuators for biomedical applications in areas such as smart prosthesis, implantable biosensors and biomechanical signal monitoring, among others. For acquiring or applying the electrical signal from/to the piezoelectric material, suitable electrodes can be produced from Ti based coatings with tailored multifunctional properties: conductivity and antibacterial characteristics through Ag inclusions. This work reports on Ti{sub 1−x}Ag{sub x} electrodes with different Ag/Ti atomic ratios deposited by dc and pulsed magnetron sputtering at room temperature on poly(vinylidene fluoride), PVDF. The X-ray diffraction (XRD) results revealed that the deposition conditions preserve the polymer structure and suggested the presence of crystalline Tiβ phase in pure titanium coating and fcc-Ag phase in pure silver coating. According to the results obtained from scanning electron microscopy (SEM) analysis, the coatings are homogeneous and no clusters were found; since β-PVDF is anisotropic, the deposited coatings replicate the underlying substrate surface. Sheet resistivity values show a typical behavior of a binary alloy system, with low resistivity values for coatings of zone 1 (Ti rich) and zone 3 (Ag rich) and a slightly higher resistivity values in zone 2. The piezoelectricity of the different samples show similar values.

  16. The Reliability of Microalloyed Sn-Ag-Cu Solder Interconnections Under Cyclic Thermal and Mechanical Shock Loading

    Science.gov (United States)

    Mattila, Toni T.; Hokka, Jussi; Paulasto-Kröckel, Mervi

    2014-11-01

    In this study, the performance of three microalloyed Sn-Ag-Cu solder interconnection compositions (Sn-3.1Ag-0.52Cu, Sn-3.0Ag-0.52Cu-0.24Bi, and Sn-1.1Ag-0.52Cu-0.1Ni) was compared under mechanical shock loading (JESD22-B111 standard) and cyclic thermal loading (40 ± 125°C, 42 min cycle) conditions. In the drop tests, the component boards with the low-silver nickel-containing composition (Sn-Ag-Cu-Ni) showed the highest average number of drops-to-failure, while those with the bismuth-containing alloy (Sn-Ag-Cu-Bi) showed the lowest. Results of the thermal cycling tests showed that boards with Sn-Ag-Cu-Bi interconnections performed the best, while those with Sn-Ag-Cu-Ni performed the worst. Sn-Ag-Cu was placed in the middle in both tests. In this paper, we demonstrate that solder strength is an essential reliability factor and that higher strength can be beneficial for thermal cycling reliability but detrimental to drop reliability. We discuss these findings from the perspective of the microstructures and mechanical properties of the three solder interconnection compositions and, based on a comprehensive literature review, investigate how the differences in the solder compositions influence the mechanical properties of the interconnections and discuss how the differences are reflected in the failure mechanisms under both loading conditions.

  17. Atomic-scale investigation of interface-facilitated deformation twinning in severely deformed Ag-Cu nanolamellar composites

    Energy Technology Data Exchange (ETDEWEB)

    An, X. H., E-mail: anxianghai@gmail.com, E-mail: xiaozhou.liao@sydenye.edu.au; Cao, Y.; Liao, X. Z., E-mail: anxianghai@gmail.com, E-mail: xiaozhou.liao@sydenye.edu.au [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales 2006 (Australia); Zhu, S. M.; Nie, J. F. [Department of Materials Engineering, Monash University, Melbourne, Victoria 3800 (Australia); Kawasaki, M. [Division of Materials Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Ringer, S. P. [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales 2006 (Australia); Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, New South Wales 2006 (Australia); Langdon, T. G. [Departments of Aerospace and Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-1453 (United States); Materials Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom); Zhu, Y. T. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919 (United States); School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing (China)

    2015-07-06

    We report an atomic-scale investigation of interface-facilitated deformation twinning behaviour in Ag-Cu nanolamellar composites. Profuse twinning activities in Ag supply partial dislocations to directly transmit across the Ag-Cu lamellar interface that promotes deformation twinning in the neighbouring Cu lamellae although the interface is severely deformed. The trans-interface twin bands change the local structure at the interface. Our analysis suggests that the orientation relationship and interfacial structure between neighbouring Ag-Cu lamellae play a crucial role in such special interface-facilitated twinning behaviour.

  18. Atomic-scale investigation of interface-facilitated deformation twinning in severely deformed Ag-Cu nanolamellar composites

    International Nuclear Information System (INIS)

    We report an atomic-scale investigation of interface-facilitated deformation twinning behaviour in Ag-Cu nanolamellar composites. Profuse twinning activities in Ag supply partial dislocations to directly transmit across the Ag-Cu lamellar interface that promotes deformation twinning in the neighbouring Cu lamellae although the interface is severely deformed. The trans-interface twin bands change the local structure at the interface. Our analysis suggests that the orientation relationship and interfacial structure between neighbouring Ag-Cu lamellae play a crucial role in such special interface-facilitated twinning behaviour

  19. Feather-like Ag@TiO2 nanostructures as plasmonic antenna to enhance optoelectronic performance.

    Science.gov (United States)

    Wang, Yang; Zhai, Jin; Song, Yanlin

    2015-02-21

    The feather-like Ag@TiO2 nanostructures including 1-dimensional (1D) Ag nanowires and 2-dimensional (2D) TiO2 possess the features of fast electron transmission by one-dimensional metal nanomaterials, high light harvesting and electron collection by feather-like nanostructures like "plasmonic antenna" at the same time. We introduce them into photoanodes to enhance the conversion efficiency in DSSCs. The best efficiency (η) of the electrode reaches 8.16% compared with that of the pure TiO2 electrode (6.41%). The energy conversion efficiency and photocurrent density of photoanodes with Ag@TiO2 nanostructures are enhanced by about 14.5% and 27.8%, respectively, as compared with those of the pure TiO2 cells. The photoelectric properties of electrodes are investigated by optical and electrochemical measurements. Hence, the improved performances are attributed to the "plasmonic antenna" effect due to Ag@TiO2 anchored in TiO2 films. PMID:25597348

  20. The study of mechanical properties of Sn-Ag-Cu lead-free solders with different Ag contents and Ni doping under different strain rates and temperatures

    International Nuclear Information System (INIS)

    Research highlights: → The effect of Ag content on the mechanical properties of Sn-Ag-Cu lead-free solders was studied systematically and the Ag content and strain rate-dependent material constitutive models have been developed for the first time. The effect of Ag content on the microstructures of Sn-Ag-Cu solder was also studied. The effect of Ni doping on the mechanical properties of Sn-1.0Ag-0.5Cu solder was also investigated and the temperature and strain rate-dependent material constitutive model has been developed for Sn-1.0Ag-0.5Cu-0.02Ni solder, which is essential for finite element simulation for assessment of reliability of electronic assembly with such solder. - Abstract: In this paper, the tensile tests were conducted at 25 oC to investigate the effect of Ag content and Ni doping on the microstructures and mechanical properties of Sn-3.0Ag-0.5Cu, Sn-2.0Ag-0.5Cu, Sn-1.0Ag-0.5Cu, Sn-1.0Ag-0.5Cu-0.05Ni and Sn-1.0Ag-0.5Cu-0.02Ni solders. The effect of strain rate on mechanical properties was investigated for each solder using stain rates of 10-5 s-1, 10-4 s-1, 10-3 s-1, 10-2 s-1 and 10-1 s-1. In addition, the effect of temperature on mechanical properties was investigated for Sn-1.0Ag-0.5Cu-0.02Ni solder by conducting tests at -35 oC, 25 oC, 75 oC and 125 oC. Test results show that the elastic modulus, yield stress and ultimate tensile strength increase with increasing strain rate and Ag content, but they decrease with increasing temperature. The elastic modulus, yield stress and ultimate tensile strength are lower and the elongation is larger for Sn-1.0Ag-0.5Cu-0.05Ni solder compared with Sn-1.0Ag-0.5Cu-0.02Ni solder. The strain rate and Ag content dependent mechanical property models have been developed for Sn-Ag-Cu solders for the first time. In addition, the temperature and rate-dependent mechanical property models have also been developed for Sn-1.0Ag-0.5Cu-0.02Ni solder. The microstructures of solders were also analyzed. The Ag content affects Ag3Sn

  1. Preparation and optical properties of silica Ag-Cu alloy core-shell composite colloids

    International Nuclear Information System (INIS)

    The silica Ag-Cu alloy core-shell composite colloids have been successfully synthesized by an electroless plating approach to explore the possibility of modifying the plasmon resonance at the nanoshell surface by varying the metal nanoshell composition for the first time. The surface plasmon resonance of the composite colloids increases in intensity and shifts towards longer, then shorter wavelengths as the Cu/Ag ratio in the alloy shell is increased. The variations in intensity of the surface plasmon resonance with the Cu/Ag ratio obviously affect the Raman bands of the silica colloid core. The report here may supply a new technique to effectively modify the surface plasmon resonance. - Graphical abstract: The silica Ag-Cu alloy core-shell colloids have been successfully synthesized to explore the possibility of modifying the surface plasmon resonance (SPR) by varying the metal nanoshell composition for the first time. Varying the Cu/Ag ratio of the alloy nanoshell has obvious influences on the SPR of the composite colloids and the Raman bands of the amorphous silica core

  2. Spin-Diffusion Lengths in Dilute Cu(Ge) and Ag(Sn) Alloys

    OpenAIRE

    Fowler, Q.; Richard, B.; Sharma, A.; Theodoropoulou, N.; Loloee, R.; Pratt Jr., W. P.; Bass, J.

    2008-01-01

    We use current-perpendicular-to-plane (CPP) exchange-biased spin-valves to directly measure spin diffusion lengths lsf for N = Cu(2.1 at.%Ge) and Ag(3.6 at.%Sn) alloys. We find lsf(Cu2%Ge)) = 117+10-6 nm and lsf(Ag4%Sn)= 39 +/- 3 nm. The good agreement of this lsf(Cu2%Ge) with the value lsf(Cu2%Ge) = 121 +/- 10 nm derived from an independent spin-orbit cross-section measurement for Ge in Cu, quantitatively validates the use of Valet-Fert theory for CPP-MR data analysis to layer thicknesses se...

  3. Microstructural characterization and compression properties of TiC0.61/Cu(Al) composite synthesized from Cu and Ti3AlC2 powders

    International Nuclear Information System (INIS)

    Highlights: • Submicro-layered TiC0.61/Cu(Al) nanocomposite. • MAX phase. • High yield stress. • Deformation mechanism. - Abstract: A new submicro-layered TiC0.61/Cu(Al) composite has been prepared by hot-pressing a mixture of 50 vol.% Ti3AlC2 and 50 vol.% Cu powders at 1150 °C and 30 MPa. It is shown that the initial reinforcement Ti3AlC2 particles have, after synthesis, an unusual microstructure, which consists of submicron-thick layers of TiC0.61 and Cu(Al) alloy. Both the width of the TiC0.61 and Cu(Al) layers are ∼150 nm. Thus, the Ti3AlC2 particles are decomposed into the TiC0.61 phase, while the additional Al atoms provided by Ti3AlC2 diffuse into the molten Cu matrix at high temperature. Compression tests were performed at constant strain rate in the temperature range 20–800 °C. The new designed TiC0.61/Cu(Al) composite has both a high yield stress, σ0.2 measured at 0.2% strain offset, and a high ultimate compressive strength, σUCS, which is attributed to strong interface bonding between TiC0.61 and Cu(Al) phase. For instance, at 20 and 200 °C, σ0.2 is 770 MPa and 700 MPa, while σUCS is 1.18 GPa and 1 GPa, respectively. Plastic deformation takes place in the Cu(Al) matrix. Wavy slip lines are observed indicating that cross-slip could be the dominant deformation mechanism

  4. Effect of TiB2 on Tribological Properties of TiAl Self-lubricating Composites Containing Ag at Elevated Temperature

    Science.gov (United States)

    Yao, Jie; Shi, Xiaoliang; Zhai, Wenzheng; Ibrahim, Ahmed Mohamed Mahmoud; Xu, Zengshi; Song, Siyuan; Chen, Long; Zhu, Qingshuai; Xiao, Yecheng; Zhang, Qiaoxin

    2015-01-01

    TiB2 was chosen to further improve the tribological properties of TiAl matrix self-lubricating composites containing Ag. The possible synergetic action of a combination of TiB2 and Ag was investigated using a pin-on-disk high temperature tribometer from room temperature to 600 °C. The tribological test results indicated that the addition of TiB2 obviously enhanced the wear resistance of the composites over a wide temperature range. Moreover, the composites containing TiB2 had a low friction coefficient at 600 °C. The subsurface analysis of cross sections of worn surfaces showed that TiB2 played the role in wear-resistant skeleton and restricted the plastic flow of Ag during dry friction process. The investigation showed that TiB2 and Ag could exhibit good synergistic effect on improving the tribological properties of composites.

  5. Enhancement of visible light activity in Ag modified SnO2/TiO2

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Ag modified SnO2/TiO2 nanoparticles were synthesized by a modified sol–gel method. • As-prepared samples have a small and uniform particle size of about 20 nm. • As-prepared samples exhibit an excellent photo-catalytic efficiency on the degradation of MB. • As-prepared samples maintain high photo-chemical stability after 5 catalytic cycles. - Abstract: Ag modified SnO2/TiO2 nanoparticles were successfully prepared by a modified sol–gel method, without adding any acid or alkali. The entire preparation differs from the traditional sol–gel synthesis of TiO2 that the reaction can get controlled by adjusting the flow speed of water vapor. Ultraviolet–visible diffuse reflectance spectra (UV–vis) and spin-trapping electron paramagnetic resonance (EPR) were used to forecast the photocatalytic activity of the samples, and the results were proved by the degradation of methylene blue solution under visible light. Compared with pure TiO2, as-prepared Ag modified SnO2/TiO2 nanoparticles exhibited not only an enhanced photocatalytic activity but also an improved stability. Among all of samples, the composite with 0.5% of Ag and 1% of Sn showed the best photocatalytic performance and stability. Further increasing the Ag proportion will result in the decrease of the photocatalytic activity. A relative mechanism was proposed and discussed in detail

  6. SiO2/TiO2/n-Si/Ag(Cr)/TiO2 thin films with superhydrophilicity and low-emissivity

    Science.gov (United States)

    Loka, Chadrasekhar; Ryeol Park, Kyoung; Lee, Kee-Sun

    2016-01-01

    In this study, SiO2/TiO2/n-Si/Ag(Cr)/TiO2 multilayer structures have been designed and deposited by the RF and DC magnetron sputtering at room temperature. The as-deposited TiO2/glass films which are initially amorphous in nature were subjected to post annealing at 673 K for anatase phase TiO2. The anatase TiO2 films showed an optical bandgap ˜3.32 eV. The Ag(Cr)/TiO2 showed very low-emissivity (low-e) value ˜0.081 which is evaluated by using the sheet resistance (6.51 Ω/□) of the films. All the deposited films showed high visible transmittance (˜81%) and high infrared reflectance (72%) which are recorded by using the UV-vis-NIR spectrophotometer. In addition, experimentally obtained optical properties were in good agreement with the simulation data. The TiO2/n-Si heterojunction concept has been employed to enhance the superhydrophilicity of the deposited multilayer stack, TiO2/n-Si/Ag(Cr)/TiO2 films exhibited best superhydrophilicity with water contact angle ˜2°. The deposited multilayer structures SiO2/TiO2/n-Si/Ag(Cr)/TiO2 and TiO2/n-Si/Ag(Cr)/TiO2 achieved significant low-e and superhydrophilicity.

  7. Diffusion of Ag, Au and Cs implants in MAX phase Ti3SiC2

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Weilin; Henager, Charles H.; Varga, Tamas; Jung, Hee Joon; Overman, Nicole R.; Zhang, Chonghong; Gou, Jie

    2015-05-16

    MAX phases (M: early transition metal; A: elements in group 13 or 14; X: C or N), such as titanium silicon carbide (Ti3SiC2), have a unique combination of both metallic and ceramic properties, which make them attractive for potential nuclear applications. Ti3SiC2 has been considered as a possible fuel cladding material. This study reports on the diffusivities of fission product surrogates (Ag and Cs) and a noble metal Au (with diffusion behavior similar to Ag) in this ternary compound at elevated temperatures, as well as in dual-phase nanocomposite of Ti3SiC2/3C-SiC and polycrystalline CVD 3C-SiC for behavior comparisons. Samples were implanted with Ag, Au or Cs ions and characterized with various methods, including x-ray diffraction, electron backscatter diffraction, energy dispersive x-ray spectroscopy, Rutherford backscattering spectrometry, helium ion microscopy, and transmission electron microscopy. The results show that in contrast to immobile Ag in 3C-SiC, there is a significant outward diffusion of Ag in Ti3SiC2 within the dual-phase nanocomposite during Ag ion implantation at 873 K. Similar behavior of Au in polycrystalline Ti3SiC2 was also observed. Cs out-diffusion and release from Ti3SiC2 occurred during post-implantation thermal annealing at 973 K. This study suggests caution and further studies in consideration of Ti3SiC2 as a fuel cladding material for advanced nuclear reactors operating at very high temperatures.

  8. Diffusion of Ag, Au and Cs implants in MAX phase Ti3SiC2

    Science.gov (United States)

    Jiang, Weilin; Henager, Charles H.; Varga, Tamas; Jung, Hee Joon; Overman, Nicole R.; Zhang, Chonghong; Gou, Jie

    2015-07-01

    MAX phases (M: early transition metal; A: elements in group 13 or 14; X: C or N), such as titanium silicon carbide (Ti3SiC2), have a unique combination of both metallic and ceramic properties, which make them attractive for potential nuclear applications. Ti3SiC2 has been considered as a possible fuel cladding material. This study reports on the diffusivities of fission product surrogates (Ag and Cs) and a noble metal Au (with diffusion behavior similar to Ag) in this ternary compound at elevated temperatures, as well as in dual-phase nanocomposite of Ti3SiC2/3C-SiC and polycrystalline CVD 3C-SiC for behavior comparisons. Samples were implanted with Ag, Au or Cs ions and characterized with various methods, including X-ray diffraction, electron backscatter diffraction, energy dispersive X-ray spectroscopy, Rutherford backscattering spectrometry, helium ion microscopy, and transmission electron microscopy. The results show that in contrast to immobile Ag in 3C-SiC, there is a significant outward diffusion of Ag in Ti3SiC2 within the dual-phase nanocomposite during Ag ion implantation at 873 K. Similar behavior of Au in polycrystalline Ti3SiC2 was also observed. Cs out-diffusion and release from Ti3SiC2 occurred during post-implantation thermal annealing at 973 K. This study suggests caution and further studies in consideration of Ti3SiC2 as a fuel cladding material for advanced nuclear reactors operating at very high temperatures.

  9. Highly stable and efficient Ag/AgCl-TiO2 photocatalyst: Preparation, characterization, and application in the treatment of aqueous hazardous pollutants

    International Nuclear Information System (INIS)

    Graphical abstract: A new plasmonic photocatalyst of Ag–AgCl/TiO2 was prepared by deposition–precipitation and photoreduction. This photocatalyst exhibited efficient photocatalytic activity for the degradation of 4-chlorophenol and photoreduction Cr(VI) under visible light irradiation. Highlights: ► The preparation procedure for Ag–AgCl/TiO2 was convenient and feasible. ► Ag–AgCl/TiO2 was very efficient under visible-light irradiation. ► Ag–AgCl/TiO2 can photodegrade 4-chlorophenol and Cr(VI) effectively. ► The surface plasmon resonance effect of Ag0 nanoparticles played a key role. - Abstract: A new plasmonic photocatalyst of Ag–AgCl-TiO2 was prepared by deposition–precipitation and photoreduction. This photocatalyst exhibited efficient photocatalytic activity for the degradation of 4-chlorophenol and photoreduction of Cr(VI) ion under visible light irradiation. Its high photocatalytic activity can be attributed to the surface plasmon resonance effect of Ag nanoparticles, which were highly dispersed on the surface of Ag–AgCl-TiO2. N2 adsorption and desorption isotherm spectra, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy were used to determine the correlation between the micro-structure and the catalytic properties of the as-prepared photocatalysts.

  10. Effects of TiO2 coating dosage and operational parameters on a TiO2/Ag photocatalysis system for decolorizing Procion red MX-5B

    International Nuclear Information System (INIS)

    In this study, titanium dioxide (TiO2) powder was coated onto the surface of a dendritic silver (Ag) carrier to synthesize TiO2/Ag for decolorizing Procion red MX-5B (MX-5B), and related operation factors were also studied. The results showed that even without ultraviolet-A (UVA) irradiation, the Ag carrier from the TiO2/Ag catalyst had oxidizing ability, which could effectively degrade MX-5B color, but TiO2 was ineffective. In addition, TiO2 from TiO2/Ag demonstrated photocatalysis performance when irradiated, and the Ag carrier further showed an electron-scavenging ability to mitigate electron-hole pair recombination, which can improve the photocatalytic efficacy. With the oxidization and electron-scavenging ability of Ag and the photocatalysis ability of TiO2, TiO2/Ag can decolor MX-5B more efficiently than TiO2. The heavier Ag carrier also improves the solid-liquid separation of nano-TiO2, making TiO2/Ag more suitable for application in slurry systems of photocatalytic water treatment. When the TiO2/Ag coating ratio was 50% by weight, there was a sufficient amount of TiO2 on Ag's surface with a good distribution, and it exhibited a good photocatalysis decolorizing effect. In a study of how operational factors impact the decolorizing of MX-5B in the TiO2/Ag photocatalysis system with UVA irradiation (UVA-TiO2/Ag), the decolorization efficiency was optimal when the solution was maintained at pH 6.35. The addition of 0.01 M hydrogen peroxide (H2O2) aided the photocatalysis decolorization efficiency, although excessive H2O2 reacted with hydroxyl free radicals and decreased the active groups in the system, thereby reducing the photocatalysis activity. An operating temperature of 40 deg. C was conducive to MX-5B decolorization, which was better than operating at room temperature.

  11. An in-situ synthesis of Ag/AgCl/TiO2/hierarchical porous magnesian material and its photocatalytic performance

    Science.gov (United States)

    Yang, Lu; Wang, Fazhou; Shu, Chang; Liu, Peng; Zhang, Wenqin; Hu, Shuguang

    2016-02-01

    The absorption ability and photocatalytic activity of photocatalytic materials play important roles in improving the pollutants removal effects. Herein, we reported a new kind of photocatalytic material, which was synthesized by simultaneously designing hierarchical porous magnesian (PM) substrate and TiO2 catalyst modification. Particularly, PM substrate could be facilely prepared by controlling its crystal phase (Phase 5, Mg3Cl(OH)5·4H2O), while Ag/AgCl particles modification of TiO2 could be achieved by in situ ion exchange between Ag+ and above crystal Phase. Physiochemical analysis shows that Ag/AgCl/TiO2/PM material has higher visible and ultraviolet light absorption response, and excellent gas absorption performance compared to other controls. These suggested that Ag/AgCl/TiO2/PM material could produce more efficient photocatalytic effects. Its photocatalytic reaction rate was 5.21 and 30.57 times higher than that of TiO2/PM and TiO2/imporous magnesian substrate, respectively. Thus, this material and its intergration synthesis method could provide a novel strategy for high-efficiency application and modification of TiO2 photocatalyst in engineering filed.

  12. The Process of TiB2-Cu Composite Phase and Structure Formation during Combustion Synthesis

    Institute of Scientific and Technical Information of China (English)

    XU Qiang; ZHANG Xinghong; HAN Jiecai; PAN Wei

    2006-01-01

    The reaction process of combustion synthesis for TiB2- Cu was investigated in detail using combustion-wave arresting experiment, X-ray diffraction (XRD) analysis, SEM analysis and differential thermal analysis ( DTA ). The XRD analysis results for the different parts of the quenched specimen shaw that TiCux intermetallic phase firstly forms with the propagation of combustion wave, and then Ti1.87 B50 and Ti3 B4 metastable phases come forth due to the diffusion of B atoms and finally the stable TiB2 phase forms because of the continuous diffusion of B atoms. The formation of TiB2 phase is not completed by one step, but undergoes several transient processes. The process of reaction synthesis for Ti-B-Cu ternary system can be divided into three main stages: melting of Cu and Ti, and the formation of Cu- Ti melt and few TiCux , TiBx intermetallic phases; large numbers of TiCux intermetallic phases formation and some fine TiB2 particles precipitation; and the TiB2 particles coarsening and the stable TiB2 and Cu two phases formation in the final product.

  13. Preparation and photoelectrochemical performance of TiO2/Ag2Se interface composite film

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Coupling TiO2 with a narrow band gap semiconductor acting as the photosensitizer has attracted much attention in solar energy exploitation. In this work,the porous TiO2 film was first formed on the conducting glass plate (CGP) substrate by the decomposition of polyethylene glycol (PEG) mixing in titanium hydroxide sol at 450℃. Then,the TiO2/Ag2Se interface composite film was fabricated by interface reaction of AgNO3 with NaSeSO3 on the activated surface of porous TiO2 film. The results of SEM and XRD analyses indicated that the porous TiO2 layer was made up of the anatase crystal,and the Ag2Se layer was made up of congregative small particles that have low-temperature α-phase structure. Due to its efficient charge separation for the photo-induced electron-hole pairs,the TiO2/Ag2Se interface composite film as-prepared has good photovoltaic property and high photocurrent response for visible light,which have been confirmed by the photoelectrochemical measurements.

  14. Anti-biofilm efficacy of low temperature processed AgCl–TiO2 nanocomposite coating

    International Nuclear Information System (INIS)

    Biofilms are a major concern in the medical settings and food industries due to their high tolerance to antibiotics, biocides and mechanical stress. Currently, the development of novel methods to control biofilm formation is being actively pursued. In the present study, sol–gel coatings of AgCl–TiO2 nanoparticles are presented as potential anti-biofilm agents, wherein TiO2 acts as a good supporting matrix to prevent aggregation of silver and facilitates its controlled release. Low-temperature processed AgCl–TiO2 nanocomposite coatings inhibit biofilm formation by Escherichia coli, Staphylococcus epidermidis and Pseudomonas aeruginosa. In vitro biofilm assay experiments demonstrated that AgCl–TiO2 nanocomposite coated surfaces, inhibited the development of biofilms over a period of 10 days as confirmed by scanning electron microscopy. The silver release kinetics exhibited an initial high release, followed by a slow and sustained release. The anti-biofilm efficacy of the coatings could be attributed to the release of silver, which prevents the initial bacterial adhesion required for biofilm formation. - Highlights: • Potential of AgCl–TiO2 nanocomposite coating to inhibit biofilm formation is exhibited. • Initial rapid release followed by later slow and sustained release of silver obtained. • TiO2 being porous and inorganic in nature acts as a good supporting matrix

  15. Investigation of superionic AgCuSe conductor by inelastic neutron scattering

    International Nuclear Information System (INIS)

    The lattice dynamics of the ternary superionic compound AgCuSe was studied for both superionic α-phase and the non-superionic β-phase. Inelastic neutron scattering in polycrystalline β-AgCuSe indicates the presence of low-energy peaks in the dynamic structure factor at energy 3-4 meV. Most probably, these low-energy modes are caused by acoustic phonons. The main difference between the neutron weighted generalized function of phonon states density of the non-superionic and superionic silver-copper selenide consists in a smearing of the strongly pronounced maxima at 10 and 20 meV in α-AgCuSe

  16. Enlace y estereoquímica en compuestos monovalentes de Cu, Ag y Au

    OpenAIRE

    Carvajal Barba, Mª Àngels

    2004-01-01

    [spa] En esta tesis se tratan diversos aspectos de la química de Cu(I), Ag(I) y Au(I). En primer lugar se estudia sistemáticamente la capacidad de los funcionales de la densidad B3LYP, PBE0 y PBE1 para tratar las interacciones d10···d10 y otros tipos de interacciones intermoleculares, tales como enlace de hidrógeno fuerte, débil y moderado e interacciones de Van der Waals. Se estudia el problema del número de coordinación en compuestos de Cu(I), Ag(I) y Au(I): mientras que Cu(I) y Ag(I) forma...

  17. Thermodynamic properties of the liquid Ag-Cu-Sn lead-free solder alloys

    International Nuclear Information System (INIS)

    The electromotive force measurement method was employed to determine the thermodynamic properties of liquid Ag-Cu-Sn alloys using solid electrolyte galvanic cells as shown below: Kanthal+Re,Ag-Cu-Sn,SnO2|YttriastabilizedZirconia|air,Pt,pO2=0.21atm Measurements were carried out for three cross-sections with constant Ag/Cu ratio equal to: 1/3, 1 and 3 and for tin compositions ranging from 10 up to 80 at.%, every 10%, resulting in a total of 24 different alloy compositions. The temperature of the measurements varied within the range from 973 to 1325 K. A linear dependence of the e.m.f. on temperature was observed for all alloy compositions and the appropriate line equations were derived. Tin activities were calculated as function of composition and temperature. Results were presented in tables and figures.

  18. Ag and CdS nanoparticles co-sensitized TiO2 nanotubes for enhancing visible photoelectrochemical performance

    International Nuclear Information System (INIS)

    Highlights: ► Ag and CdS nanoparticles co-sensitized TiO2 nanotubes were fabricated by the SILAR method. ► The co-sensitization expands the photoresponse range of TiO2 NTs to 668.7 nm. ► Visible light photocurrents and photocatalytic activities of CdS–Ag/TiO2 NTs were studied. ► The electron transfer mechanism of CdS–Ag/TiO2 NTs was proposed. - Abstract: The Ag and CdS nanoparticles co-sensitization of TiO2 nanotubes (CdS–Ag/TiO2 NTs) were prepared by successive ionic layer adsorption and reaction (SILAR) technique. The phase composition, morphology and optical property were characterized by the X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis diffusion reflection spectroscopy (DRS). The co-modification of Ag and CdS nanoparticles expanded the photoresponse range of TiO2 NTs from ultraviolet region to 668.7 nm, and the CdS–Ag/TiO2 NTs prepared by SILAR deposition of 5 cycles exhibited higher visible photocurrent and stability against photocorrosion. The detailed electrons transfer mechanism of CdS–Ag/TiO2 NTs was proposed, and photocatalytic activity toward degradation of methyl orange (MO) under visible-light irradiation was also investigated.

  19. Effects of plasmon excitation on photocatalytic activity of Ag/TiO 2 and Au/TiO2 nanocomposites

    DEFF Research Database (Denmark)

    Sellappan, Raja; González-Posada, Fernando; Chakarov, Dinko;

    2013-01-01

    Model nanocomposite photocatalysts consisting of undoped TiO2 films with optically active Ag or Au nanoparticles (NPs) were designed, fabricated, and examined to address the role of plasmon excitations in their performance. Different composition configurations were tested in which the NPs were ei...

  20. New Cu-Free Ti-Based Composites with Residual Amorphous Matrix

    Directory of Open Access Journals (Sweden)

    Mircea Nicoara

    2016-04-01

    Full Text Available Titanium-based bulk metallic glasses (BMGs are considered to have potential for biomedical applications because they combine favorable mechanical properties and good biocompatibility. Copper represents the most common alloying element, which provides high amorphization capacity, but reports emphasizing cytotoxic effects of this element have risen concerns about possible effects on human health. A new copper-free alloy with atomic composition Ti42Zr10Pd14Ag26Sn8, in which Cu is completely replaced by Ag, was formulated based on Morinaga’s d-electron alloy design theory. Following this theory, the actual amount of alloying elements, which defines the values of covalent bond strength Bo and d-orbital energy Md, situates the newly designed alloy inside the BMG domain. By mean of centrifugal casting, cylindrical rods with diameters between 2 and 5 mm were fabricated from this new alloy. Differential scanning calorimetry (DSC and X-rays diffraction (XRD, as well as microstructural analyses using optical and scanning electron microscopy (OM/SEM revealed an interesting structure characterized by liquid phase-separated formation of crystalline Ag, as well as metastable intermetallic phases embedded in residual amorphous phases.

  1. Syntheses, structures, and optical properties of Ba4MInSe6 (M=Cu, Ag)

    International Nuclear Information System (INIS)

    Two new quaternary chalcogenides, namely Ba4MInSe6 (M=Cu, Ag), were synthesized by solid state reactions. These two isostructural compounds adopt the Ba2MnS3 structure type in the orthorhombic space group Pnma. In the structure, the M and In atoms randomly occupy one crystallographic unique metal position with the molar ratio of 1:1 The (M/In)Se4 tetrahedra are connected to each other by corner-sharing to form one-dimensional chains along the b direction, which are separated by mono-capped trigonal prismatically coordinated Ba atoms. Based on the diffuse reflectance spectrum, the optical band gaps were determined to be 2.23(2) and 2.41(2) eV for Ba4CuInSe6 and Ba4AgInSe6, respectively. - Graphical abstract: In the structure of Ba4MInSe6 (M=Cu, Ag), the (M/In)Se4 tetrahedra are connected by corner-sharing to form chains along the b direction, which are separated by Ba atoms. Highlights: ► Two new quaternary chalcogenides, Ba4MInSe6 (M=Cu, Ag), were synthesized. ► Ba4MInSe6 (M=Cu, Ag) are isostructural and crystallize in the Ba2MnS3 structure type ► The (M/In)Se4 tetrahedra are connected by corner-sharing to form chains along the b direction. ► The chains are separated by mono-capped trigonal prismatically coordinated Ba atoms. ► The optical band gaps are 2.23(2) and 2.41(2) eV for Ba4CuInSe6 and Ba4AgInSe6, respectively.

  2. Structural and magnetic phase transitions in CeCu6 -xTx (T =Ag ,Pd )

    Science.gov (United States)

    Poudel, L.; de la Cruz, C.; Payzant, E. A.; May, A. F.; Koehler, M.; Garlea, V. O.; Taylor, A. E.; Parker, D. S.; Cao, H. B.; McGuire, M. A.; Tian, W.; Matsuda, M.; Jeen, H.; Lee, H. N.; Hong, T.; Calder, S.; Zhou, H. D.; Lumsden, M. D.; Keppens, V.; Mandrus, D.; Christianson, A. D.

    2015-12-01

    The structural and the magnetic properties of CeCu6 -xAgx (0 ≤x ≤0.85 ) and CeCu6 -xPdx (0 ≤x ≤0.4 ) have been studied using neutron diffraction, resonant ultrasound spectroscopy (RUS), x-ray diffraction measurements, and first principles calculations. The structural and magnetic phase diagrams of CeCu6 -xAgx and CeCu6 -xPdx as a function of Ag/Pd composition are reported. The end member, CeCu6, undergoes a structural phase transition from an orthorhombic (P n m a ) to a monoclinic (P 21/c ) phase at 240 K. In CeCu6 -xAgx , the structural phase transition temperature (Ts) decreases linearly with Ag concentration and extrapolates to zero at xS ≈0.1 . The structural transition in CeCu6 -xPdx remains unperturbed with Pd substitution within the range of our study. The lattice constant b slightly decreases with Ag/Pd doping, whereas a and c increase with an overall increase in the unit cell volume. Both systems, CeCu6 -xAgx and CeCu6 -xPdx , exhibit a magnetic quantum critical point (QCP), at x ≈0.2 and x ≈0.05 , respectively. Near the QCP, long range antiferromagnetic ordering takes place at an incommensurate wave vector (δ10 δ2), where δ1˜0.62 ,δ2˜0.25 ,x =0.125 for CeCu6 -xPdx and δ1˜0.64 ,δ2˜0.3 ,x =0.3 for CeCu6 -xAgx . The magnetic structure consists of an amplitude modulation of the Ce moments which are aligned along the c axis of the orthorhombic unit cell.

  3. Antifungal activity of Ag:hydroxyapatite thin films synthesized by pulsed laser deposition on Ti and Ti modified by TiO2 nanotubes substrates

    Science.gov (United States)

    Eraković, S.; Janković, A.; Ristoscu, C.; Duta, L.; Serban, N.; Visan, A.; Mihailescu, I. N.; Stan, G. E.; Socol, M.; Iordache, O.; Dumitrescu, I.; Luculescu, C. R.; Janaćković, Dj.; Miškovic-Stanković, V.

    2014-02-01

    Hydroxyapatite (HA) is a widely used biomaterial for implant thin films, largely recognized for its excellent capability to chemically bond to hard tissue inducing the osteogenesis without immune response from human tissues. Nowadays, intense research efforts are focused on development of antimicrobial HA doped thin films. In particular, HA doped with Ag (Ag:HA) is expected to inhibit the attachment of microbes and contamination of metallic implant surface. We herewith report on nano-sized HA and Ag:HA thin films synthesized by pulsed laser deposition on pure Ti and Ti modified with 100 nm diameter TiO2 nanotubes (fabricated by anodization of Ti plates) substrates. The HA-based thin films were characterized by SEM, AFM, EDS, FTIR, and XRD. The cytotoxic activity was tested with HEp2 cells against controls. The antifungal efficiency of the deposited layers was tested against the Candida albicans and Aspergillus niger strains. The Ti substrates modified with TiO2 nanotubes covered with Ag:HA thin films showed the highest antifungal activity.

  4. Cluster reaction of [Ag8]-/[Cu8]- with chlorine: Evidence for the harpoon mechanism?

    Science.gov (United States)

    Luo, Zhixun; Berkdemir, Cüneyt; Smith, Jordan C.; Castleman, A. W.

    2013-09-01

    To examine the question whether the harpoon mechanism can account for the reactive behavior of microscopic charged systems, we have investigated the reactivity of coinage metal clusters in gas phase. Our studies reveal that the reactivity between [Cu8]-/[Ag8]- and chlorine gas is consistent with the harpoon mechanism. An increased reactive cross section is noted through our theoretical estimation based on two methods, ascribed to a long-range transfer of valence electrons from the [Cu8]-/[Ag8]- cluster to chlorine. Insights into this reactivity will be of interest to other researchers working on obtaining a better understanding of the reaction mechanisms of such superatomic species.

  5. Topological description of mechanical behavior of Cu, Ag and Au: A first-principle study

    Directory of Open Access Journals (Sweden)

    M Saghayezhian

    2011-12-01

    Full Text Available  Mechanical properties and stress-strain curves of Cu, Ag and Au single crystals are calculated using ab initio methods. Elastic and Plastic regions are scrutinized. Yield stress and slope of these curves can shed light on brittlenesss and ductility of these metals that prove Cu, despite its high ultimate tensile strength, is less ductile than Au and Ag. Analysis of topology of charge density along with stress-strain curves shows that the elastic-plastic transition accompanies topological transition and for these metals, both transitions occur in the same strain. Some charactristics of critical point, especially bond points, are inspected.

  6. A new dental powder from nanocrystalline melt-spun Ag-Sn-Cu alloy ribbons

    International Nuclear Information System (INIS)

    A new non-gamma-two dental powder has been developed from nanocrystalline melt-spun Ag-Sn-Cu alloy ribbons. The amalgam made from this powder exhibits excellent properties for dental filling. The nanocrystalline microstructure was found for the first time in as-spun and heat treated Ag(27-28)Sn(9-32) Cu alloy ribbons, using X-ray diffraction, scanning electron microscopy and energy-dispersive spectroscopy. As-spun ribbons exhibited a multi-phase microstructure with preferred existence of β (Ag4Sn) phase formed during rapid solidification (RS) due to supersaturating of copper (Cu) atoms and homogenous nanostructure with subgrain size of about (40-50) nm, which seems to be developed during RS process and can be caused by eutectic reaction of the Ag3Sn/Ag4Sn-Cu3Sn system. In heat treated ribbons the clustering of Cu atoms was always favored and stable in an ageing temperature and time interval determined by Cu content. The heat treatment led to essential changes of subgrain morphology, resulted in the appearance of large-angle boundaries with fine Cu3Sn precipitates and forming typical recrystallization twins. Such a microstructure variation in melt-spun ribbons could eventually yield enhanced technological, clinical and physical properties of the dental products, controlled by the ADA Specification N deg 1 and reported before. Thus, using the rapid solidification technique a new non-gamma-two dental material of high quality, nanocrystalline ribbon powder, can be produced. Copyright (2003) AD-TECH - International Foundation for the Advancement of Technology Ltd

  7. Influence of Microstructure Refinement on Strain Strengthening Effect of Cu-Ag Alloy in situ Filamentary Composites

    Institute of Scientific and Technical Information of China (English)

    Ning Yuantao; Zhang Xiaohui; Wu Yuejun

    2007-01-01

    The Cu-10Ag and Cu-1OAg-RE (RE = Ce, Y) alloys in situ filamentary composites were prepared. The relationships of the ultimate tensile strengths ( UTS) and microstructure changes of the composites were studied. With increasing of the true strain η, the sizes of the Ag filaments in the composites reduce according to a negative exponential function of η : d = d0·exp (-0. 228η) , and the UTS of the composites increase also according to a exponential function of η, σcu/Ag = σ0(cu) + [Kcu/Ag d0 -1/2 ]exp( η/3), here d0 is a coefficient related to the original size of Ag phase. The strain strengthening follows a two-stage strengthening effect. The strengthening mechanisms are related to changes of microstructure in the deformation process. At the low true strain stage, the strengthening is mainly caused by the working hardening controlled by dislocation increasing; at the high true strain stage, the strengthening is mainly caused by the super-fine Ag filaments and the large coherent interfaces between the Ag filaments and Cu matrix. The trace RE additions and the rapid solidification obviously refine scales of the Ag filament of the composites, and therefore obviously increased the strain strengthening rate. The microstructure refinement of the composites, especially the refinement of Ag filament, is the main reason of the high strain strengthening effect in Cu-Ag alloy in situ filamentary composites.

  8. Effect of water absorption of dielectric underlayers on crystal orientation in Al-Si-Cu/Ti/TiN/Ti metallization

    Science.gov (United States)

    Yoshida, Tomoyuki; Hashimoto, Shoji; Hosokawa, Hideki; Ohwaki, Takeshi; Mitsushima, Yasuichi; Taga, Yasunori

    1997-05-01

    The influence of the exposure of underlying dielectric (phophosilicate glass and borophosphosilicate glass) films to a humid air ambient on crystallographic orientations in Al-Si-Cu/Ti/TiN/Ti layered structures has been investigated as a function of the boron content and exposure time of the dielectric films. The Al(111) orientation in the layered structures was found to improve drastically with increasing boron content and exposure time of the dielectric films. The full width at half maximum value of an Al(111) x-ray rocking curve reached less than 1°. It was also found that the Al-Si-Cu surface becomes smoother and the average grain size increases as the Al(111) orientation improves. The improved Al(111) orientation was attributed to the improved Ti(002) orientation of the bottom Ti films. The mechanism of the improved Ti(002) orientation was investigated. It was confirmed that the improved orientation is closely related with the surface concentration of the absorbed water in the dielectric films. Further, it was demonstrated that interconnects fabricated from the improved layered structure have excellent electromigration performance.

  9. Effect of microstructure on corrosion behavior of Ag-30Cu-27Sn alloy in vitro media

    International Nuclear Information System (INIS)

    Highlights: • High cooling rates decrease the number of Ag intermetallic particles in Cu-rich phase. • Increasing cooling rate improves corrosion behavior of Ag-30Cu-27Sn dental alloy. • Cathode/anode ratio in Cu-rich phases determines the corrosion behavior of alloy. - Abstract: In the present work, three simple heat treatment cycles were used to study the effects of microstructure on electrochemical corrosion behavior of Ag-30Cu-27Sn dental alloy. The electrochemical impedance spectroscopy (EIS) measurements and potentiodynamic polarization tests were carried out to investigate the corrosion behavior of as-cast and heat treated samples in synthetic saliva solution. The presence of intermetallic compounds were studied by X-ray diffraction method (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray detector (EDAX). The microstructural observations and electrochemical corrosion results revealed that, increasing the cooling rate improves the corrosion behavior of under investigation samples. Improvement of the corrosion behavior is attributed to reducing the area of fine distributed Ag3Sn islands in the Cu-rich matrix which decrease the cathode/anode ratio of microgalvanic cells

  10. Effect of microstructure on corrosion behavior of Ag-30Cu-27Sn alloy in vitro media

    Energy Technology Data Exchange (ETDEWEB)

    Salehisaki, Mehdi, E-mail: mehdisasaki@ut.ac.ir [Department of Materials Science and Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Aryana, Maryam, E-mail: maryam.aryana@yahoo.com [AGSP Engineering Company, Biomaterial Research Unit, R.N: 12786 Kerman (Iran, Islamic Republic of)

    2014-04-01

    Highlights: • High cooling rates decrease the number of Ag intermetallic particles in Cu-rich phase. • Increasing cooling rate improves corrosion behavior of Ag-30Cu-27Sn dental alloy. • Cathode/anode ratio in Cu-rich phases determines the corrosion behavior of alloy. - Abstract: In the present work, three simple heat treatment cycles were used to study the effects of microstructure on electrochemical corrosion behavior of Ag-30Cu-27Sn dental alloy. The electrochemical impedance spectroscopy (EIS) measurements and potentiodynamic polarization tests were carried out to investigate the corrosion behavior of as-cast and heat treated samples in synthetic saliva solution. The presence of intermetallic compounds were studied by X-ray diffraction method (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray detector (EDAX). The microstructural observations and electrochemical corrosion results revealed that, increasing the cooling rate improves the corrosion behavior of under investigation samples. Improvement of the corrosion behavior is attributed to reducing the area of fine distributed Ag{sub 3}Sn islands in the Cu-rich matrix which decrease the cathode/anode ratio of microgalvanic cells.

  11. Global optimization and oxygen dissociation on polyicosahedral Ag32Cu6 core-shell cluster for alkaline fuel cells

    Science.gov (United States)

    Zhang, N.; Chen, F. Y.; Wu, X. Q.

    2015-07-01

    The structure of 38 atoms Ag-Cu cluster is studied by using a combination of a genetic algorithm global optimization technique and density functional theory (DFT) calculations. It is demonstrated that the truncated octahedral (TO) Ag32Cu6 core-shell cluster is less stable than the polyicosahedral (pIh) Ag32Cu6 core-shell cluster from the atomistic models and the DFT calculation shows an agreeable result, so the newfound pIh Ag32Cu6 core-shell cluster is further investigated for potential application for O2 dissociation in oxygen reduction reaction (ORR). The activation energy barrier for the O2 dissociation on pIh Ag32Cu6 core-shell cluster is 0.715 eV, where the d-band center is -3.395 eV and the density of states at the Fermi energy level is maximal for the favorable absorption site, indicating that the catalytic activity is attributed to a maximal charge transfer between an oxygen molecule and the pIh Ag32Cu6 core-shell cluster. This work revises the earlier idea that Ag32Cu6 core-shell nanoparticles are not suitable as ORR catalysts and confirms that Ag-Cu nanoalloy is a potential candidate to substitute noble Pt-based catalyst in alkaline fuel cells.

  12. A study of a fast ionic conductor - Ag[sub 1-x]Cu[sub x]I

    Energy Technology Data Exchange (ETDEWEB)

    Nalini, B. (Dept. of Physics, Bharathiar Univ., Coimbatore (India) Dept. of Physics, Indian Inst. of Tech., Madras (India)); Selvasekarapandian, S. (Dept. of Physics, Bharathiar Univ., Coimbatore (India) Dept. of Physics, Indian Inst. of Tech., Madras (India)); Jayashree, J. (Dept. of Physics, Bharathiar Univ., Coimbatore (India) Dept. of Physics, Indian Inst. of Tech., Madras (India)); Hariharan, K. (Dept. of Physics, Bharathiar Univ., Coimbatore (India) Dept. of Physics, Indian Inst. of Tech., Madras (India))

    1994-01-01

    The Conductivity of AgI-CuI system has been studied. Two molar ratios of the system Ag[sub 1-x]Cu[sub x]I with x=0.05 and 0.15 have been taken. The transition temperatures are observed with conductivity measurements. (orig.)

  13. Irradiation induced dissolution of Cu and growth of Ag nanoclusters in Cu/Ag ion-exchanged soda-lime glass

    CERN Document Server

    Manikandan, D; Magudapathy, P; Nair, K G M

    2002-01-01

    Complex metal nanoclusters of Cu/Ag are formed in a soda-lime glass matrix by sequential copper and silver ion-exchange followed by ion irradiation. Optical absorption measurements showed signature of copper clusters alone in the Cu/Ag ion-exchanged sample. Irradiation of the ion-exchanged sample with He sup + ions of energy 100 keV of different fluences resulted in the growth of the silver clusters with, the optical absorption spectrum exhibiting two peaks corresponding to the surface plasmon resonance of copper and silver in the same matrix. It was found that with increase in fluence the silver clusters begin to grow while the already formed copper clusters segregate, which can be visualized from the absorption spectra, where the copper band disappears while the silver band grows with the increase in dose. Vacuum annealing of the Cu/Ag ion-exchanged samples resulted in complete disappearance of copper clusters while the silver clusters grew till they attained saturation. The glancing incidence X-ray diffrac...

  14. Synthesis and optimization of Ag-TiO2 composite nanofibers for photocatalytic treatment of impaired water sources.

    Science.gov (United States)

    Nalbandian, Michael J; Zhang, Miluo; Sanchez, Joel; Kim, Seil; Choa, Yong-Ho; Cwiertny, David M; Myung, Nosang V

    2015-12-15

    In this work, Ag-TiO2 composite nanofibers were fabricated by electrospinning, where the composition and crystallinity were tuned by controlling the precursor composition and annealing conditions. Characterization revealed that bulk-embedded Ag nanoparticles inhibited anatase-to-rutile phase transformation and a decrease in band gap from 3.2 down to 2.8 eV with increase in the Ag content. The photocatalytic activity of 0.5 at.% Ag-TiO2 nanofibers toward phenol degradation was the greatest, outperforming both unmodified TiO2 nanofibers and commercially available TiO2 Aeroxide(®) P25 by a factor of ∼3. The high reactivity of the low content Ag-TiO2 nanofibers can be attributed to the addition of electron traps, which provide efficient carrier separation and, therefore, decreased recombination. However, further increase in Ag content led to lower photoreactivity, most likely due to the growth of the Ag nanoparticles, which suggests an optimal size of 2 to 3 nm for the Ag nanoparticles at 0.5 at.% provided the greatest photoreactivity. Ag-TiO2 nanofibers show great promise as innovative and highly performing nanomaterials for future nanotechnology-based treatment systems, particularly when the photoreactivity demonstrate herein is used in synergy with the established antimicrobial activity of nano-Ag. PMID:26101968

  15. Lattice location and perturbed angular correlation studies of implanted Ag in SrTiO3

    International Nuclear Information System (INIS)

    Lattice site location and local environment characterization of implanted 111Ag in SrTiO3 by means of the emission channeling (EC) and γ-γ perturbed angular correlation (PAC) techniques are reported. The angular distribution of β- particles emitted from the 111Ag decay was monitored with a position-sensitive detector as a function of annealing temperature up to 900 deg. C. In the as-implanted state Ag occupies several lattice sites in SrTiO3. Upon annealing, near-Sr and near-Ti occupancies increased to 64% and 18%, while an octahedral interstitial fraction vanished. Ag atoms on near-Sr and near-Ti sites are still displaced by ∼0.2 A from ideal cubic positions. Subsequent PAC measurements confirmed that ∼20% of 111Ag atoms are in specific sites of non-cubic environment, characterized by a unique electrical-field-gradient (EFG), while ∼80% were subject to a wide EFG distribution

  16. The characteristics of novel bimodal Ag-TiO2 nanoparticles generated by hybrid laser-ultrasonic technique

    Science.gov (United States)

    Hamad, Abubaker; Li, Lin; Liu, Zhu; Zhong, Xiang Li; Burke, Grace; Wang, Tao

    2016-04-01

    Silver-titania (Ag-TiO2) nanoparticles with smaller Ag nanoparticles attached to larger TiO2 nanoparticles were generated by hybrid ultrasonic vibration and picosecond laser ablation of Ag and Ti bulk targets in deionised water, for the first time. The laser has a wavelength of 1064 nm and a pulse duration of 10 ps. It was observed that without the ultrasonic vibration, Ag and TiO2 nanoparticles did not combine, thus the role of ultrasonic vibration is essential. In addition, colloidal TiO2 and Ag nanoparticles were generated separately for comparison under the same laser beam characteristics and process conditions. The absorption spectra of colloidal Ag-TiO2 cluster nanoparticles were examined by UV-Vis spectroscopy, and size distribution was characterised using transmission electron microscopy. The morphology and composition of Ag-TiO2 nanoparticles were examined using scanning transmission electron microscopy in high-angle annular dark field, and energy-dispersive X-ray spectroscopy. The crystalline structures were investigated by X-ray diffraction. The size of larger TiO2 particles was in the range 30-150 nm, and the smaller-sized Ag nanoparticles attached to the TiO2 was mainly in the range of 10-15 nm. The yield is more than 50 % with the remaining nanoparticles in the form of uncombined Ag and TiO2. The nanoparticles generated had strong antibacterial effects as tested against E. coli. A discussion is given on the role of ultrasonic vibration in the formation of Ag-TiO2 hybrid nanoparticles by picosecond laser ablation.

  17. Photocatalytic degradation of dairy effluent using AgTiO2 nanostructures/polyurethane nanofiber membrane

    DEFF Research Database (Denmark)

    Kanjwal, Muzafar Ahmad; Barakat, Nasser A.M.; Chronakis, Ioannis S.

    2015-01-01

    Dairy effluent (DE) is environmentally toxic and needs special attention. Photocatalytic degradation of DE was studied using novel polyurethane (PU)-based membranes. Typically, silver-titanium dioxide nanofibers (AgTiO2 NFs) and silver-titanium dioxide nanoparticles (AgTiO2 NPs) were individually...

  18. Deep-level transient spectroscopy of TiO2/CuInS2 heterojunctions

    NARCIS (Netherlands)

    Nanu, M.; Boulch, F.; Schoonman, J.; Goossens, A.

    2005-01-01

    Deep-level transient spectroscopy (DLTS) has been used to measure the concentration and energy position of deep electronic states in CuInS2. Flat TiO2∣CuInS2 heterojunctions as well as TiO2-CuInS2 nanocomposites have been investigated. Subband-gap electronic states in CuInS2 films are mostly due to

  19. Phase transformation and microstructural changes during ageing process of an Ag-Pd-Cu-Au alloy

    International Nuclear Information System (INIS)

    Age-hardening behaviour and the related phase transformation and microstructural changes during isothermal ageing process were studied to elucidate the age-hardening mechanism of an Ag-based dental casting alloy composed of Ag-Pd-Cu-Au-Zn, Ir and In by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) observations and energy dispersive spectroscopic microanalysis (EDS). In the hardness test at 350 and 400 deg. C, the hardness of the solution-treated specimen began to increase and reached a maximum value with increasing ageing time, and subsequently the hardness decreased gradually. By considering XRD results and SEM observations together, the solution-treated specimen consisted of three phases, the Ag-rich α1 phase as a matrix, the Cu-Pd α2 phase and the CuPd β phase with a CsCl-type as particle-like structures. By ageing the solution-treated specimen, the Ag-rich α1 and Cu-Pd α2 phases were transformed into the Ag-rich α'1 and Cu3Pd α'2 phases, respectively. The CuPd β phase with a CsCl-type was not changed apparently during the ageing process. From the results of the hardness test, XRD study, SEM observations and EDS analysis, it could be derived that the hardness increased by the diffusion and precipitation of the Cu-rich phase from the Ag-rich matrix during the early stage of phase transformation of α1 into α'1 and that the progress of coarsening of the Cu-rich precipitates with an entanglement structure caused the hardness decrease during the later stage of phase transformation of α1 into α'1. The particle-like structures composed of the Cu-Pd α2 and the CuPd β phase with a CsCl-type contributed little to the hardness increase which occurred in the early stage of aging process

  20. Sensitive and selective detection of Hg2+ and Cu2+ ions by fluorescent Ag nanoclusters synthesized via a hydrothermal method

    Science.gov (United States)

    Liu, Jing; Ren, Xiangling; Meng, Xianwei; Fang, Zheng; Tang, Fangqiong

    2013-09-01

    An easily prepared fluorescent Ag nanoclusters (Ag NCs) probe for the sensitive and selective detection of Hg2+ and Cu2+ ions was developed here. The Ag NCs were synthesized by using polymethacrylic acid sodium salt as a template via a convenient hydrothermal process. The as-prepared fluorescent Ag NCs were monodispersed, uniform and less than 2 nm in diameter, and can be quenched in the presence of mercury (Hg2+) or copper (Cu2+) ions. Excellent linear relationships existed between the quenching degree of the Ag NCs and the concentrations of Hg2+ or Cu2+ ions in the range of 10 nM to 20 μM or 10 nM to 30 μM, respectively. By using ethylenediaminetetraacetate (EDTA) as the masking agent of Cu2+, Hg2+ was exclusively detected in coexistence with Cu2+ with high sensitivity (LOD = 10 nM), which also provided a reusable detection method for Cu2+. Furthermore, the different quenching phenomena caused by the two metals ions such as changes in visible colour, shifts of UV absorbance peaks and changes in size of Ag NCs make it easy to distinguish between them. Therefore the easily synthesized fluorescent Ag NCs may have great potential as Hg2+ and Cu2+ ions sensors.An easily prepared fluorescent Ag nanoclusters (Ag NCs) probe for the sensitive and selective detection of Hg2+ and Cu2+ ions was developed here. The Ag NCs were synthesized by using polymethacrylic acid sodium salt as a template via a convenient hydrothermal process. The as-prepared fluorescent Ag NCs were monodispersed, uniform and less than 2 nm in diameter, and can be quenched in the presence of mercury (Hg2+) or copper (Cu2+) ions. Excellent linear relationships existed between the quenching degree of the Ag NCs and the concentrations of Hg2+ or Cu2+ ions in the range of 10 nM to 20 μM or 10 nM to 30 μM, respectively. By using ethylenediaminetetraacetate (EDTA) as the masking agent of Cu2+, Hg2+ was exclusively detected in coexistence with Cu2+ with high sensitivity (LOD = 10 nM), which also provided a

  1. Influence of Doped Cu-Zn on Structure and Properties of TiN Films

    OpenAIRE

    WEI Chun-Bei,GONG Chun-Zhi,TIAN Xiu-Bo,YANG Shi-Qin

    2009-01-01

    Cu-Zn doped TiN films were fabricated on stainless steel by hybrid magnetron sputtering. Influences of Cu and Zn concentration on structure and properties (such as microhardness, wear resistance and corrosion resistance) of the films were investigated. The results indicate that growth of TiN grains is blocked by doped Cu and Zn and TiN grain size decreases with increasing Cu and Zn concentration. In contrast, high Cu and Zn content induces coarse structure due to the growth of copper grains. ...

  2. Ag2S/CdS/TiO2 Nanotube Array Films with High Photocurrent Density by Spotting Sample Method

    OpenAIRE

    Sun, Hong; Zhao, Peini; Zhang, Fanjun; Liu, Yuliang; Hao, Jingcheng

    2015-01-01

    Ag2S/CdS/TiO2 hybrid nanotube array films (Ag2S/CdS/TNTs) were prepared by selectively depositing a narrow-gap semiconductor—Ag2S (0.9 eV) quantum dots (QDs)—in the local domain of the CdS/TiO2 nanotube array films by spotting sample method (SSM). The improvement of sunlight absorption ability and photocurrent density of titanium dioxide (TiO2) nanotube array films (TNTs) which were obtained by anodic oxidation method was realized because of modifying semiconductor QDs. The CdS/TNTs, Ag2S/TNT...

  3. Synthesis and characterization of Ag@Cu nano/microstructure ordered arrays as SERS-active substrates

    Science.gov (United States)

    Zhang, Pinhua; Cui, Guangliang; Xiao, Chuanhai; Zhang, Mingzhe; Chen, Li; Shi, Changmin

    2016-06-01

    We fabricated an Ag decorated Cu (Ag@Cu) nano/microstructure ordered array by facile template-free 2D electrodeposition combined with a galvanic reduction method for SERS applications. The Cu nano/microstructure ordered arrays were first synthesized by a 2D electrodeposition method, then Ag nanocubes were decorated on the arrays by galvanic reduction without any capping agent. The pollution-free surface and edge-to-face heterostructure of Ag nanocubes and Cu nano/microstructure arrays provide the powerful field-enhancements for SERS performance. The results verified that the Ag@Cu nano/microstructure ordered arrays have excellent activity for 4-Mercaptopyridine, and the sensitivity limit is as low as 10‑8 M. Therefore, this facile route provides a useful platform for the fabrication of a SERS substrate based on nano/microstructure ordered arrays.

  4. SiO2/TiO2/Ag multilayered microspheres: Preparation, characterization, and enhanced infrared radiation property

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Novel SiO2/TiO2/Ag core–shell multilayer microspheres with tunable TiO2 and Ag layers were prepared. • Complete Ag shell was fabricated by Ag-seeds growth process. • The SiO2/TiO2/Ag core–shell composites exhibited the good infrared emissivity value than SiO2 and SiO2/TiO2 substrates. - Abstract: SiO2/TiO2/Ag core–shell multilayered microspheres were successfully synthesized by the combination of anatase of TiO2 modification on the surfaces of SiO2 spheres and subsequent Ag nanoparticles deposition and Ag shell growth with face-centered cubic (fcc) Ag. The composites were characterized by TEM, FT-IR, UV–vis, Raman spectroscopy and XRD, respectively. The infrared emissivity values during 8–14 μm wavelengths of the composites were measured. The results revealed that TiO2 thin layers with the thickness of ∼10 nm were coated onto the SiO2 spheres of ∼220 nm in diameter. The thickness of the TiO2 layers was controlled by varying the amount of TBOT precursor. Homogeneous Ag nanoparticles of ∼20 nm in size were successfully deposited by ultrasound on the surfaces of SiO2/TiO2 composites, followed by complete covering of Ag shell. The infrared emissivity value of the SiO2/TiO2 composites was decreased than that of pure SiO2. Moreover, the introduction of the Ag brought the remarkably lower infrared emissivity value of the SiO2/TiO2/Ag multilayered microspheres with the lowest value down to 0.424. Strong chemical effects in the interface of SiO2/TiO2 core–shell composites and high reflection performance of the metal Ag are two decisive factors for the improved infrared radiation performance of the SiO2/TiO2/Ag multilayered microspheres

  5. SiO{sub 2}/TiO{sub 2}/Ag multilayered microspheres: Preparation, characterization, and enhanced infrared radiation property

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Xiaoyun, E-mail: creekye@163.com; Cai, Shuguang; Zheng, Chan; Xiao, Xueqing; Hua, Nengbin; Huang, Yanyi

    2015-08-01

    Graphical abstract: - Highlights: • Novel SiO{sub 2}/TiO{sub 2}/Ag core–shell multilayer microspheres with tunable TiO{sub 2} and Ag layers were prepared. • Complete Ag shell was fabricated by Ag-seeds growth process. • The SiO{sub 2}/TiO{sub 2}/Ag core–shell composites exhibited the good infrared emissivity value than SiO{sub 2} and SiO{sub 2}/TiO{sub 2} substrates. - Abstract: SiO{sub 2}/TiO{sub 2}/Ag core–shell multilayered microspheres were successfully synthesized by the combination of anatase of TiO{sub 2} modification on the surfaces of SiO{sub 2} spheres and subsequent Ag nanoparticles deposition and Ag shell growth with face-centered cubic (fcc) Ag. The composites were characterized by TEM, FT-IR, UV–vis, Raman spectroscopy and XRD, respectively. The infrared emissivity values during 8–14 μm wavelengths of the composites were measured. The results revealed that TiO{sub 2} thin layers with the thickness of ∼10 nm were coated onto the SiO{sub 2} spheres of ∼220 nm in diameter. The thickness of the TiO{sub 2} layers was controlled by varying the amount of TBOT precursor. Homogeneous Ag nanoparticles of ∼20 nm in size were successfully deposited by ultrasound on the surfaces of SiO{sub 2}/TiO{sub 2} composites, followed by complete covering of Ag shell. The infrared emissivity value of the SiO{sub 2}/TiO{sub 2} composites was decreased than that of pure SiO{sub 2}. Moreover, the introduction of the Ag brought the remarkably lower infrared emissivity value of the SiO{sub 2}/TiO{sub 2}/Ag multilayered microspheres with the lowest value down to 0.424. Strong chemical effects in the interface of SiO{sub 2}/TiO{sub 2} core–shell composites and high reflection performance of the metal Ag are two decisive factors for the improved infrared radiation performance of the SiO{sub 2}/TiO{sub 2}/Ag multilayered microspheres.

  6. Substitution effects of Ag/Cu and Al/Cu on Y123 samples: Hall anomaly and transport properties

    OpenAIRE

    Nazarzadehmoafi, M.; V Daadmehr; Rezakhani, A. T.; S Falahati; F Saeb; Rezaei, S. Barekat

    2011-01-01

    The Hall effect and its associated anomalies offer an important means for describing superconducting property in cuprate compounds. Here, we investigate the electron- and hole-doping effects (implemented through Al- and Ag-doping, respectively) on the Hall effect and transport properties of Y123 superconducting materials (YBa2Cu3-xXxO7-d; X= Ag, Al). The Hall anomaly, in both normal and vortex states, generally depends on multiple factors, such as temperature, magnetic field, and amount/type ...

  7. Microstructure and Strength of Brazed Joints of Ti3Al Base Alloy with Cu-P Filler Metal

    Institute of Scientific and Technical Information of China (English)

    Peng HE; Jicai FENG; Heng ZHOU

    2005-01-01

    Brazing of Ti3Al alloys with the filler metal Cu-P was carried out at 1173~1273 K for 60~1800 s. When products are brazed, the optimum brazing parameters are as follows: brazing temperature is 1215~1225 K; brazing time is 250~300 s. Four kinds of reaction products were observed during the brazing of Ti3Al alloys with the filler metal Cu-P, i.e., Ti3Al phase with a small quantity of Cu (Ti3Al(Cu)) formed close to the Ti3Al alloy; the TiCu intermetallic compounds layer and the Cu3P intermetallic compounds layer formed between Ti3Al(Cu) and the filler metal, and a Cu-base solid solution formed with the dispersed Cu3P in the middle of the joint. The interfacial structure of brazed Ti3Al alloys joints with the filler metal Cu-P is Ti3Al/Ti3Al(Cu)/TiCu/Cu3P/Cu solid solution (Cu3P)/Cu3P/TiCu/Ti3Al(Cu)/Ti3Al, and this structure will not change with brazing time once it forms. The thickness of TiCu+Cu3P intermetallic compounds increases with brazing time according to a parabolic law. The activation energy Q and the growth velocity K0 of reaction layer TiCu+Cu3P in the brazed joints of Ti3Al alloys with the filler metal Cu-P are 286 k J/mol and 0.0821 m2/s, respectively, and growth formula was y2=0.0821exp(-34421.59/T)t.Careful control of the growth for the reaction layer TiCu+Cu3P can influence the final joint strength. The formation of the intermetallic compounds TiCu+Cu3P results in embrittlement of the joint and poor joint properties. The Cu-P filler metal is not fit for obtaining a high-quality joint of Ti3Al brazed.

  8. Preparation of mesoporous Ag-containing TiO{sub 2} heterojunction film and its photocatalytic property

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Q. Y., E-mail: wangqingyao0532@163.com [Ludong University, School of Chemistry and Materials Science (China); Qiao, J. L. [Jilin Agricultural University, College of Horticulture (China); Cui, X. Y. [Mudanjiang Medical University, School of Public Health (China); Zhong, J. S. [Hangzhou Dianzi University, College of Materials and Environmental Engineering (China); Xu, Y. B.; Zhang, S. H.; Zhang, Q. H.; Chang, P.; Li, M.; Zhang, C.; Gao, S. M., E-mail: gaosm@ustc.edu [Ludong University, School of Chemistry and Materials Science (China)

    2015-03-15

    Mesoporous Ag/TiO{sub 2} heterojunction films (Ag-MTHF) with enhanced photocatalytic activity were synthesized by a three-step approach including an electrochemical anodization technique followed by successive ionic layer adsorption and reaction (SILAR) and solvothermal methods. The distribution of Ag nanoparticles on the inner structure of the mesoporous TiO{sub 2} film was confirmed by field emission scanning electron (FE-SEM) and transmission electron microscopes (TEM). The formation progress of the novel mesoporous Ag/TiO{sub 2} nanojunction film with Ag average diameter of 17 nm was illuminated. The formed nanojunction between Ag and TiO{sub 2} nanoparticles largely enhanced the photocatalytic degradation of methyl orangey (MO), and the corresponding mechanism was proposed.

  9. Low turn-on field and high field emission current density from Ag/TiO2 nanocomposite

    Science.gov (United States)

    Patil, Girish P.; Deore, Amol B.; Bagal, Vivekanand S.; Late, Dattatray J.; More, Mahendra A.; Chavan, Padmakar G.

    2016-07-01

    High current density of 1.24 mA/cm2 was drawn at an applied field of 4.4 V/μm from Ag/TiO2 nanocomposite. Also the turn-on field has been reduced from 3.9 V/μm to 2.7 V/μm for the emission current density of 10 μA/cm2. Ag/TiO2 nanocomposite was synthesized by using UV-switchable reducing agent. TiO2 nanotube wall was decorated by Ag nanoparticles with average diameter of 17 nm. To the best of our knowledge this is the first report on the field emission studies of Ag/TiO2 nanocomposite. Simple synthesis route coupled with superior field emission properties indicate the possible use of Ag/TiO2 nanocomposite for micro/nanoelectronic devices.

  10. The preparation of thermally stable TiNx/Ag(Mo)/TiNx ultrathin films by magnetron sputtering

    International Nuclear Information System (INIS)

    Thermally stable optically selective coatings are indispensable for low emissivity (low-e) applications. Low-e coatings effectively reduce energy loss from the building glazing systems by allowing high visible transmittance and reflecting most near-infrared radiation of the solar spectrum. In the present study, we investigated the thermal stability and optical properties of TiNx/Ag(Mo)/TiNx films deposited on glass substrates by using rf and dc magnetron sputtering at room temperature. The deposited multilayer stacks were annealed up to 873 K for 1 h in air ambient and a rigorous analysis was presented on the structure, microstructure, topography, chemical composition, and optical properties by grazing incidence X-ray diffraction, high resolution transmission electron microscopy, scanning electron microscopy, atomic force microscopy, Auger electron spectroscopy, and Ultraviolet–visible–near infrared spectrophotometer, respectively. The results revealed that the proposed structure was thermally stable with dense and smooth microstructure until 773 K; in addition, noteworthy inward/outward diffusion of silver was not observed due to the good diffusion barrier performance of TiNx. An abrupt rise in root mean square roughness and locally isolated islands like structures was observed at 873 K annealing temperature. The deposited films showed high transmittance in the visible region and high reflectance in the infrared region of the solar radiation spectrum. - Highlights: • TiNx/Ag(Mo)/TiNx/films were thermally durable until 773 K. • High visible transmittance was obtained by adopting the amorphous TiNx films. • Ag(Mo) film was protected until 773 K by partial oxidation of TiNx layers

  11. Synthesis and visible light photoactivity of anatase Ag, and garlic loaded TiO2 nanocrystalline catalyst

    Science.gov (United States)

    An excellent visible light activated Ag and S doped TiO2 nanocatalyst was prepared by using AgNO3 and garlic (Allium sativum) as Ag+ and sulfur sources, respectively. The catalyst resisted the change from anatase to rutile phase even at calcination at 700 oC. The photocatalytic e...

  12. The photo-catalytic activities of MP (M = Ba, Ca, Cu, Sr, Ag; P = PO43-, HPO42-) microparticles

    Science.gov (United States)

    Zhang, Fan; Shi, Yuanji; Zhao, Zongshan; Song, Weijie; Cheng, Yang

    2014-02-01

    For the good performance of apatite-based materials in the removal of dyes and their environment-friendly advantage, five kinds of apatite microparticles of MP (M = Ba, Ca, Cu, Sr, Ag; P = PO43-, HPO42-) were synthesized by a simple precipitation method and their photo-catalytic properties were invested. Better performance in the decolorization of methyl orange (MO) under the assistance of H2O2 than that of TiO2 were obtained for all the MPs. The photo-catalytic activity was mainly affected by surface area, energy band, impurity, crystallinity and crystal structure. The DFT calculation results demonstrated that the 2p of O and 3p of P in PO43- played the main role in the photo-catalytic process. This work would be helpful to design and synthesize low cost apatite materials with good photo-catalytic performance.

  13. p-Cu2O-shell/n-TiO2-nanowire-core heterostucture photodiodes

    Directory of Open Access Journals (Sweden)

    Hsueh Ting-Jen

    2011-01-01

    Full Text Available Abstract This study reports the deposition of cuprous oxide [Cu2O] onto titanium dioxide [TiO2] nanowires [NWs] prepared on TiO2/glass templates. The average length and average diameter of these thermally oxidized and evaporated TiO2 NWs are 0.1 to 0.4 μm and 30 to 100 nm, respectively. The deposited Cu2O fills gaps between the TiO2 NWs with good step coverage to form nanoshells surrounding the TiO2 cores. The p-Cu2O/n-TiO2 NW heterostructure exhibits a rectifying behavior with a sharp turn-on at approximately 0.9 V. Furthermore, the fabricated p-Cu2O-shell/n-TiO2-nanowire-core photodiodes exhibit reasonably large photocurrent-to-dark-current contrast ratios and fast responses.

  14. Wear and corrosion resistance of anti-bacterial Ti-Cu-N coatings on titanium implants

    Science.gov (United States)

    Wu, Haibo; Zhang, Xiangyu; He, Xiaojing; Li, Meng; Huang, Xiaobo; Hang, Ruiqiang; Tang, Bin

    2014-10-01

    Anti-bacterial coatings with excellent wear and corrosion resistance play a vital role in ensuring the durability of implant materials in constant use. To this end, a novel anti-bacterial surface modification by combining magnetron sputtering with plasma nitriding was adopted in this paper to fabricate Cu-bearing Ti-based nitrides coatings (Ti-Cu-N) on titanium surface. The anti-bacterial properties of Ti-Cu-N coatings were evaluated. The microstructures and composition of the coatings were investigated by using FESEM, EDS, GDOES, XRD. The wear and corrosion resistance of the coatings were investigated. The results confirmed that an anti-bacterial Ti-Cu-N coating with a thickness of 6 μm and good adhesive strength to substrate was successfully achieved on titanium surface. As implied by XRD, the coatings were consisted of TiN, Ti2N, TiN0.3 phases. The surface micro-hardness and wear resistance of Ti-Cu-N coatings were significantly enhanced after plasma nitriding treatment. The analysis of potentiodynamic polarization curves and Nyquist plots obtained in 0.9 wt.% NaCl solution suggested that the Ti-Cu-N coatings also exhibited an excellent corrosion resistance. As mentioned above, it can be concluded that the duplex-treatment reported here was a versatile approach to develop anti-bacterial Ti-Cu-N coatings with excellent comprehensive properties on titanium implants.

  15. Optical properties of TiO2 thin films after Ag ion implantation

    International Nuclear Information System (INIS)

    Metal plasma ion implantation has being successfully developed for improving the electronic and optical properties of semiconductor materials. Prior to deposition, a TiO2 colloidal suspension was synthesized by microwave-induced thermal hydrolysis of the titanium tetrachloride aqueous solution. The TiO2 thin film was optimized to obtain a high-purity crystalline anatase phase by calcinations at 550 deg. C. The TiO2 coating was uniform without aggregation, which provided good photo conversion efficiency. Ag ion implantation into the as-calcined TiO2 thin films was conducted with 1 x 1015 ∼ 1 x 1016 ions/cm2 at 40 keV. The peak position and intensity of the photoluminescence and UV-Vis absorption spectra are quite sensitive to Ag doping. The optical characterization showed a shift in optical absorption wavelength towards infrared ray side, which was correlated with the structure variation of the Ag+ implanted TiO2. Due to the strong capability of forming compounds between the energetic silver ions and TiO2, the photoluminescence emission and UV-Vis absorption efficiencies were improved.

  16. Novel Ag@TiO{sub 2} nanocomposite synthesized by electrochemically active biofilm for nonenzymatic hydrogen peroxide sensor

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Mohammad Mansoob; Ansari, Sajid Ali; Lee, Jintae; Cho, Moo Hwan, E-mail: mhcho@ynu.ac.kr

    2013-12-01

    A novel nonenzymatic sensor for H{sub 2}O{sub 2} was developed based on an Ag@TiO{sub 2} nanocomposite synthesized using a simple and cost effective approach with an electrochemically active biofilm. The optical, structural, morphological and electrochemical properties of the as-prepared Ag@TiO{sub 2} nanocomposite were examined by UV–vis spectroscopy, X-ray diffraction, transmission electron microscopy and cyclic voltammetry (CV). The Ag@TiO{sub 2} nanocomposite was fabricated on a glassy carbon electrode (GCE) and their electrochemical performance was analyzed by CV, differential pulse voltammetry and electrochemical impedance spectroscopy. The Ag@TiO{sub 2} nanocomposite modified GCE (Ag@TiO{sub 2}/GCE) displayed excellent performance towards H{sub 2}O{sub 2} sensing at − 0.73 V in the linear response range from 0.83 μM to 43.3 μM, within a detection limit and sensitivity of 0.83 μM and ∼ 65.2328 ± 0.01 μAμM{sup −1} cm{sup −2}, respectively. In addition, Ag@TiO{sub 2}/GCE exhibited good operational reproducibility and long term stability. - Graphical abstract: Synthesis of Ag@TiO{sub 2} nanocomposite by electrochemically active biofilm for H{sub 2}O{sub 2} sensing. - Highlights: • Electrochemically active biofilm (EAB) • EAB mediated synthesis of Ag@TiO{sub 2} nanocomposite • Ag@TiO{sub 2} nanocomposite modified glassy carbon electrode • Ag@TiO{sub 2}/GCE for H{sub 2}O{sub 2} sensing • Nonenzymatic sensor for H{sub 2}O{sub 2}.

  17. Fabrication and characterization of CuO-core/TiO2-shell one-dimensional nanostructures

    International Nuclear Information System (INIS)

    We have fabricated CuO-core/TiO2-shell one-dimensional nanostructures by coating the CuO nanowires with MOCVD-TiO2. The structure of the core/shell nanowires has been investigated by using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction analysis techniques. The CuO-cores and the TiO2-shells of the as-synthesized nanowires have been found to have crystalline monoclinic CuO and crystalline tetragonal anatase TiO2 structures, respectively. The CuO-core/TiO2-shell nanowires are winding and has rougher surface, whereas the CuO nanowires are straight and have smoother surface. Influence of the substrate temperature and the growth time on the structure such as the morphology, size, and crystallographic orientation of CuO nanowires synthesized by thermal oxidation of Cu foils have also been investigated. All the nanowires have only the CuO phase synthesized at 600 deg. C, whereas those synthesized at 400 deg. C have both CuO and Cu2O phases. The highest density of CuO nanowires with long thin straight morphologies can be obtained at 600 deg. C. In addition, the growth mechanism of the CuO nanowires has been discussed.

  18. Potential energy curves for the ground and low-lying excited states of CuAg

    International Nuclear Information System (INIS)

    The ground and low-lying excited states of heteronuclear diatomic CuAg are examined by multi-reference configuration interaction (MRCI) method. Relativistic effects were treated and probed in two steps. Scalar terms were considered using the spin-free DKH Hamiltonian as a priori and spin-orbit coupling was calculated perturbatively via the spin-orbit terms of the Breit-Pauli Hamiltonian based on MRCI wavefunctions. Potential energy curves of the spin-free states and their corresponding Ω components correlating with the separated atom limits 2S(Cu) + 2S(Ag) and 2D(Cu) + 2S(Ag) are obtained. The results are in fine agreement with the experimental measurements and tentative conclusions for the ion-pair B0+ state are confirmed by our theoretical calculations. Illustrative results are presented to reveal the relative importance and magnitude of the scalar and spin-orbit effects on the spectroscopic properties of this molecule. Time dependent density functional theory calculations, using the LDA, BLYP, B3LYP, and SAOP functionals have been carried out for CuAg and the accuracy of TD-DFT has been compared with ab initio results

  19. Onset of ATC superconductivity in Ag5Pb2O6/CuO composite

    OpenAIRE

    Djurek, Danijel

    2009-01-01

    Meissner type superconductivity extending up to 13 - 18 degrees Celsius was confirmed in the composite material consisting of metallic particles Ag5Pb2O6 dispersed in an insulating CuO matrix, and superconductivity mechanism is based upon inter particle interaction acting in the quantum tunnelling regime.

  20. Short-range ferromagnetism in alloy ribbons of Fe-Cr-Si-Nb-(Ag, Cu)

    International Nuclear Information System (INIS)

    We have studied the magnetic properties of two amorphous alloy ribbons Fe72Cr6Si4Nb5B12Ag1 (FCSNB-Ag) and Fe72Cr6Si4Nb5B12Cu1 (FCSNB-Cu), prepared by using a melt-spinning technique. Magnetization (M) measurements for various temperatures (T) and magnetic fields (H) indicate that ferromagnetic-paramagnetic (FM-PM) phase transitions take place in FCSNB-Ag and FCSNB-Cu at Curie temperatures (TC ) of about 308.3 K and 322.5 K, respectively. Analyses of M - H data at different temperatures in the vicinity of the FM-PM phase transition based on the modified Arrott plot method and scaling hypothesis yielded the exponent values of β = 0.369 ± 0.005, γ = 1.359 ± 0.005 and δ = 4.7 ± 0.1 for FCSNB-Ag, and β = 0.376 ± 0.002, γ = 1.315 ± 0.006 and δ = 4.5 ± 0.1 for FCSNB-Cu. Compared with the values from theoretical models, these values are close to those expected for the 3D Heisenberg model, demonstrating the existence of short-range FM order in the amorphous alloy ribbons.

  1. Fabrication of Ag, FeNi, Cu Thin Film for Magnetic Sensor

    International Nuclear Information System (INIS)

    It has been fabricated a Ag, FeNi, Cu thin film by sputtering method. The thin film material is deposited on the glass substrate heated from 100 oC to 400 oC having dimensions of 2.5 x 1 cm2. The sputtering time of Ag, FeNi and Cu materials are 10 minutes respectively operating voltage is 2.5 kV and electrode distance 2.5 cm. The FeNi material is alloy having ratio 70% : 30%, that is the best composition formed by previous observer. On the glass substrate, there are four layers such as: the first is FeNi, second Cu, third FeNi, and the fourth, Ag. During the sputtering process the power was 40 Watts (2 kV, 20 mA). The thin film Ag, FeNi, CuFeNi was varied for variation of sputtering to get the optimum conditions of parameter process. From the sputtering result, it was produced thin films having resistivity Ro in range of 5 to 48 Ohm (magnetron operating varied magnetic field). To measure resistance influenced the external magnetic field the thin film yields was put on the external magnetic field included four points probe system. The result showed that there was some changes of the resistances (Ro - R)/ Ro % between 10 to 14 % with error 7 - 10 %. (author)

  2. (Ag,Cu)-Ta-O ternaries as high-temperature solid-lubricant coatings.

    Science.gov (United States)

    Gao, Hongyu; Otero-de-la-Roza, Alberto; Gu, Jingjing; Stone, D'Arcy; Aouadi, Samir M; Johnson, Erin R; Martini, Ashlie

    2015-07-22

    Ternary oxides have gained increasing attention due to their potential use as solid lubricants at elevated temperatures. In this work, the tribological properties of three ternary oxides-AgTaO3, CuTaO3, and CuTa2O6-were studied using a combination of density-functional theory (DFT), molecular dynamics (MD) simulations with newly developed empirical potential parameters, and experimental measurements (AgTaO3 and CuTa2O6 only). Our results show that the MD-predicted friction force follows the trend AgTaO3 film composition after sliding, quantification of Ag or Cu cluster formation at the interface during the evolution of the film in MD, and DFT energy barriers for atom migration on the material surface. All our observations are consistent with the hypothesis that the formation of metal (or metal oxide) clusters on the surface are responsible for the friction and wear behavior of these materials. PMID:26106877

  3. ZnO-(Cu/Ag)TCNQ heterostructure network over flexible platform for enhanced cold cathode application

    Science.gov (United States)

    Pal, Shreyasi; Maiti, Soumen; Narayan Maiti, Uday; Chattopadhyay, Kalyan Kumar

    2016-07-01

    Multistage field emitters consisting of organic/inorganic hybrid nanostructures with branched geometry are designed via a two-step protocol: a simple wet chemical method followed by a vapor-solid-phase technique. (Cu/Ag)TCNQ (copper/silver-7,7,8,8-tetracyanoquinodimethane) nanowires (NWs) were grown hierarchically on zinc oxide (ZnO) nanorods (NRs) to form ZnO-(Cu/Ag)TCNQ heterostructure assemblies. By monitoring the metallic Cu and Ag coating thickness on ZnO NRs, precise control over the morphology and orientations of the secondary organic NWs is achieved. In-depth analysis of electron field emission (FE) behavior of the ZnO-(Cu/Ag)TCNQ-based hierarchy suggests highest emission performance with low turn-on as well as threshold fields of 1.15 and 3.75 V μm‑1 respectively from the morphology-optimized hierarchy. Beneficial orientation of the branched organic NWs ensures sequential electric field enhancement in the consecutive stem and branches whereas its low work function eases electron emission; these aspects combined together render an overall enhancement in the emission behavior of the hybrid system. As compared to individual building units, the heterostructures show improved field electron emission. Additionally, successful construction of this novel hybrid over a fabric platform displays great potential in opening up new pathways in the highly-anticipated field of flexible electronics.

  4. Short-range Ferromagnetism in Alloy Ribbons of Fe-Cr-Si-Nb-(Ag, Cu)

    DEFF Research Database (Denmark)

    Thanh, P. Q.; Hoa, N. Q.; Chau, N.;

    2014-01-01

    We have studied the magnetic properties of two amorphous alloy ribbons Fe72Cr6Si4Nb5B12Ag1 (FCSNB-Ag) and Fe72Cr6Si4Nb5B12Cu1 (FCSNB-Cu), prepared by using a melt-spinning technique. Magnetization (M) measurements for various temperatures (T) and magnetic fields (H) indicate that ferromagnetic......-paramagnetic (FM-PM) phase transitions take place in FCSNB-Ag and FCSNB-Cu at Curie temperatures (TC) of about 308.3 K and 322.5 K, respectively. Analyses of M - H data at different temperatures in the vicinity of the FM-PM phase transition based on the modified Arrott plot method and scaling hypothesis yielded...... the exponent values of beta = 0.369 +/- 0.005, gamma = 1.359 +/- 0.005 and delta = 4.7 +/- 0.1 for FCSNB-Ag, and beta = 0.376 +/- 0.002, gamma = 1.315 +/- 0.006 and delta = 4.5 +/- 0.1 for FCSNB-Cu. Compared with the values from theoretical models, these values are close to those expected for the 3D...

  5. Thermodynamic measurements on Ag - 28% Cu nanopowders processed by mechanical alloying route

    International Nuclear Information System (INIS)

    Graphical abstract: Crystallite size (XRD measurements) and enthalpy increment (HT − H298) (drop calorimetry data) of the nanozised Ag - 28% Cu powders as a function of temperature. - Highlights: • We report relevant data for thermodynamic stability of mechanical alloyed Ag - 28% Cu nanopowders. • Enthalpy increment and heat capacity data have been measured by drop calorimetry. • The effect of milling time on the particle size and energetic parameters is evidenced. • Correlation between thermodynamic and structural data of Ag - 28% Cu nanopowders is discussed. - Abstract: The paper is devoted to the investigation of the thermodynamic properties of Ag - 28% Cu powders processed by mechanical alloying route at two different milling times (20 and 80 h). Thermodynamic properties represented by the heat capacity (Cp) and the enthalpy increment (HT − H298) have been obtained in the temperature range from ambient to 1073 K by drop calorimetry using a multi-detector high temperature calorimeter SETARAM MHTC-96. A critical comparison of the isothermal enthalpy measurements with the dynamic differential scanning calorimetric (DSC) results has been made to reveal the occurrence of the micro-relaxation process, as well as of the correlative effects of decomposition and growth processes. New features related to the effect of the milling time and crystallite size on the thermal behavior and energetic parameters were evidenced. The correlation between thermal stability and microstructure of the sample obtained after 80 h processing has been investigated by the evaluation of the in situ controlled annealing powder X-ray diffraction patterns (XRD)

  6. Ag-Cu Colloid Synthesis: Bimetallic Nanoparticle Characterisation and Thermal Treatment

    Czech Academy of Sciences Publication Activity Database

    Sopoušek, J.; Pinkas, J.; Brož, P.; Buršík, Jiří; Vykoukal, V.; Škoda, D.; Stýskalík, A.; Zobač, O.; Vřešťál, J.; Hrdlička, A.; Šimbera, J.

    2014-01-01

    Roč. 2014, ID 638964 (2014), s. 1-13. ISSN 1687-4110 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : Ag-Cu nanoparticles * DSC * TEM Subject RIV: BJ - Thermodynamics Impact factor: 1.644, year: 2014

  7. Potential energy curves for the ground and low-lying excited states of CuAg

    Energy Technology Data Exchange (ETDEWEB)

    Alizadeh, Davood; Shayesteh, Alireza, E-mail: jamshidi@ccerci.ac.ir, E-mail: ashayesteh@ut.ac.ir [School of Chemistry, College of Science, University of Tehran, 14176 Tehran (Iran, Islamic Republic of); Jamshidi, Zahra, E-mail: jamshidi@ccerci.ac.ir, E-mail: ashayesteh@ut.ac.ir [Chemistry and Chemical Engineering Research Center of Iran, 14335-186 Tehran (Iran, Islamic Republic of)

    2014-10-21

    The ground and low-lying excited states of heteronuclear diatomic CuAg are examined by multi-reference configuration interaction (MRCI) method. Relativistic effects were treated and probed in two steps. Scalar terms were considered using the spin-free DKH Hamiltonian as a priori and spin-orbit coupling was calculated perturbatively via the spin-orbit terms of the Breit-Pauli Hamiltonian based on MRCI wavefunctions. Potential energy curves of the spin-free states and their corresponding Ω components correlating with the separated atom limits {sup 2}S(Cu) + {sup 2}S(Ag) and {sup 2}D(Cu) + {sup 2}S(Ag) are obtained. The results are in fine agreement with the experimental measurements and tentative conclusions for the ion-pair B0{sup +} state are confirmed by our theoretical calculations. Illustrative results are presented to reveal the relative importance and magnitude of the scalar and spin-orbit effects on the spectroscopic properties of this molecule. Time dependent density functional theory calculations, using the LDA, BLYP, B3LYP, and SAOP functionals have been carried out for CuAg and the accuracy of TD-DFT has been compared with ab initio results.

  8. Direct in situ activation of Ag{sup 0} nanoparticles in synthesis of Ag/TiO{sub 2} and its photoactivity

    Energy Technology Data Exchange (ETDEWEB)

    Jaafar, N.F. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Jalil, A.A., E-mail: aishah@cheme.utm.my [Institute of Hydrogen Economy, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Department of Chemical Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Triwahyono, S. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Efendi, J. [Department of Chemistry, Universitas Negeri Padang, Jl. Prof. Hamka, Air Tawar, Padang, West Sumatera (Indonesia); Mukti, R.R. [Division of Inorganic and Physical Chemistry, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Jl Ganesha No. 10, Bandung 40132 (Indonesia); Jusoh, R.; Jusoh, N.W.C. [Department of Chemical Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Karim, A.H. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Salleh, N.F.M. [Department of Chemical Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Suendo, V. [Division of Inorganic and Physical Chemistry, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Jl Ganesha No. 10, Bandung 40132 (Indonesia)

    2015-05-30

    Graphical abstract: - Highlights: • Ag{sup 0} loaded on TiO{sub 2} was prepared by a direct in situ electrochemical method. • 5 wt% Ag–TiO{sub 2} demonstrated the best photocatalytic degradation of 2-CP. • Isomorphous substitution of Ag with Ti occurred to form Ti−O−Ag bonds. • Ag{sup 0} and oxygen vacancies trapped electrons to enhance e–H{sup +} separation. • Substitution of Ag in the TiO{sub 2} structure decreased the number of oxygen vacancies. - Abstract: Metallic Ag nanoparticles (Ag{sup 0}) were successfully activated using a direct in situ electrochemical method before being supported on TiO{sub 2}. Catalytic testing showed that 5 wt% Ag–TiO{sub 2} gave the highest photodegradation (94%) of 50 mg L{sup −1} 2-chlorophenol (2-CP) at pH 5 using 0.375 g L{sup −1} catalyst within 6 h, while under similar conditions, 1 wt% and 10 wt% Ag–TiO{sub 2} only gave 75% and 78% degradation, respectively. Characterization results illustrated that the photoactivity was affected by the amount of Ag{sup 0} and oxygen vacancies which act as an electrons trap to enhance the electron–hole separation. While, the Ag−O−Ti bonds formation reduced the photoactivity. The degradation followed a pseudo-first order Langmuir–Hinshelwood model where adsorption was the controlling step. Study on the effect of scavengers showed that the hole (H{sup +}) and hydroxyl radical (OH·) play important roles in the photodegradation. The regenerated photocatalyst was still stable after five cycling runs.

  9. Synthesis of C, Ag co-modified TiO2 photocatalyst and its application in waste water purification

    International Nuclear Information System (INIS)

    Monodispersed C, Ag co-modified TiO2 microspheres were successfully synthesized through a two-step method. Firstly, monodisperse spherical TiO2 particles were obtained via controlled hydrolysis of TBOT (tetrabutyltitanate) in ethanol. Secondly, the C, Ag co-modified TiO2 microspheres were prepared through a simple calcination process, in which the AgNO3 and citric acid was used as Ag and C source, respectively. The physical and chemical properties of C, Ag co-modified TiO2 microspheres were carefully studied by using XRD, SEM, TEM, Raman, PL spectra and UV–vis diffuse reflectance spectra (DRS), while the chemical states of C and Ag were discussed via EDS (energy dispersive spectrometer) and XPS. The photocatalytic activity of the as-prepared products was evaluated by photocatalytic decolorization of Rhodamine B (Rh B) aqueous solution at ambient temperature under UV and visible-light irradiation. The photocatalytic activity research shows that, with the cooperation of two modified materials, C, Ag co-modified TiO2 microspheres exhibit enhanced photocatalytic activity both in ultraviolet and visible-light region compared with that of pure TiO2 and single Ag modified TiO2 microspheres.

  10. A study on photocatalytic activity of micro-arc oxidation TiO2 films and Ag+/MAO-TiO2 composite films

    International Nuclear Information System (INIS)

    Highlights: • The optimum voltage and concentration of micro-arc oxidation (MAO) for photocatalytic activity have been studied. • The most superior treatment time and concentration for Ag+ impregnation have been discussed under the optimum MAO condition above. • Mechanism of influence on impregnation time for Ag+MAO-TiO2 composite films have been well investigated. • MAO-TiO2 films and Ag+MAO-TiO2 composite films were compared each other on photocatalytic efficiency. - Abstract: First, micro-arc oxidation (MAO) TiO2 films have been prepared on pure titanium in a phosphate-based electrolyte, and then the Ag+/MAO-TiO2 composite films have been fabricated by Ag+ impregnation in this paper. The microstructure and composition of MAO-TiO2 films and Ag+/MAO-TiO2 composite films have been studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). The photocatalytic activity of both films was evaluated by photocatalytic decolorization of methylene blue (MB) in aqueous solution as a model pollutant under sunlight irradiation simulation with homemade ultraviolet–visible spectroscopy (UV–vis). The results showed that the photocatalytic activity of MAO-TiO2 films increased with increasing the applied voltage and concentration in a certain scope. The morphology of Ag+/MAO-TiO2 composite films were of significantly difference and superior photocatalytic activity compared to the MAO-TiO2 film. Also, Ag+ impregnation was able to enhance the photocatalytic efficiency of MAO-TiO2 film

  11. A study on photocatalytic activity of micro-arc oxidation TiO{sub 2} films and Ag{sup +}/MAO-TiO{sub 2} composite films

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, N. [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University, Changzhou 213164 (China); Jiangsu Collaborative Innovation Center of Photovolatic Science and Engineering, Changzhou University, Changzhou 213164, Jiangsu (China); Song, R.G., E-mail: songrg@hotmail.com [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University, Changzhou 213164 (China); Jiangsu Collaborative Innovation Center of Photovolatic Science and Engineering, Changzhou University, Changzhou 213164, Jiangsu (China); Xiang, B.; Li, H.; Wang, Z.X.; Wang, C. [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University, Changzhou 213164 (China); Jiangsu Collaborative Innovation Center of Photovolatic Science and Engineering, Changzhou University, Changzhou 213164, Jiangsu (China)

    2015-08-30

    Highlights: • The optimum voltage and concentration of micro-arc oxidation (MAO) for photocatalytic activity have been studied. • The most superior treatment time and concentration for Ag{sup +} impregnation have been discussed under the optimum MAO condition above. • Mechanism of influence on impregnation time for Ag+MAO-TiO{sub 2} composite films have been well investigated. • MAO-TiO{sub 2} films and Ag+MAO-TiO{sub 2} composite films were compared each other on photocatalytic efficiency. - Abstract: First, micro-arc oxidation (MAO) TiO{sub 2} films have been prepared on pure titanium in a phosphate-based electrolyte, and then the Ag{sup +}/MAO-TiO{sub 2} composite films have been fabricated by Ag{sup +} impregnation in this paper. The microstructure and composition of MAO-TiO{sub 2} films and Ag{sup +}/MAO-TiO{sub 2} composite films have been studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). The photocatalytic activity of both films was evaluated by photocatalytic decolorization of methylene blue (MB) in aqueous solution as a model pollutant under sunlight irradiation simulation with homemade ultraviolet–visible spectroscopy (UV–vis). The results showed that the photocatalytic activity of MAO-TiO{sub 2} films increased with increasing the applied voltage and concentration in a certain scope. The morphology of Ag{sup +}/MAO-TiO{sub 2} composite films were of significantly difference and superior photocatalytic activity compared to the MAO-TiO{sub 2} film. Also, Ag{sup +} impregnation was able to enhance the photocatalytic efficiency of MAO-TiO{sub 2} film.

  12. High surface area Ag-TiO2 nanotubes for solar/visible-light photocatalytic degradation of ceftiofur sodium

    International Nuclear Information System (INIS)

    Highlights: • Large surface area TiO2 nanotubes have been synthesized and modified with Ag NPs. • Ag-TiO2 NTs show very good charge separation due to 1D charge delocalization. • They exhibit excellent photocatalytic degradation of CFS under UV–vis light. • It photocatalytically activates HSO5− to produce ·OH and SO4·− simultaneously. • Ag-TiO2 NTs retain their photocatalytic activity at least up to 4 cycles. -- Abstract: Titanium dioxide nanotubes (TiO2 NTs) with very high surface area (469 m2/g) have been synthesized through a simple hydrothermal method and their surface has been modified using silver nanoparticles (Ag NPs). The Ag NPs deposited TiO2 NTs (Ag-TiO2 NTs) show an extended optical response from UV to visible region coupled with a surface plasmon resonance band and thus can be utilized as a plasmonic photocatalyst. The photoluminescence intensity of TiO2 NTs is lower than that of TiO2 nanoparticles due to the delocalization of photogenerated electrons along the one dimensional nanotubes which reduces the rate of charge recombination. The Langmuir adsorption constant of Ag-TiO2 NTs (for ceftiofur sodium adsorption) is twice that of P25 TiO2. The Ag-TiO2 NTs exhibit excellent photocatalytic activity toward the degradation of ceftiofur sodium (CFS) due to high surface area and mesoporosity of TiO2 NTs. The addition of peroxomonosulfate in the photocatalytic system greatly amplifies the CFS degradation owing to the simultaneous generation of both ·OH and SO4·−. The catalyst retains its photocatalytic activity at least up to four consecutive cycles

  13. Nonvolatile bipolar resistive switching in an Ag/TiO2/Nb:SrTiO3/In device

    International Nuclear Information System (INIS)

    A TiO2 thin film was deposited on a Nb:SrTiO3 substrate by pulsed laser deposition to form an Ag/TiO2/Nb:SrTiO3/In device. The bipolar resistive switching (RS) effect of this device was investigated. The current-voltage characteristics exhibited pronounced and stable bipolar RS features. The device could be switched to a low resistance state (LRS) at forward voltage and returned to a high resistance state (HRS) at reverse voltage, and the RS ratio RHRS/RLRS reached up to 2 × 103 at a read voltage of -0.5 V. Moreover, the RS ratio could be adjusted by changing the maximum value of the forward or reverse voltage, which shows promise for multilevel memories. These results are discussed by considering carrier injection-trapped/detrapped process of the heterostructure and show high potential for nonvolatile memory applications.

  14. Influence of Ag-Au microstructure on the photoelectrocatalytic performance of TiO2 nanotube array photocatalysts.

    Science.gov (United States)

    Wang, Qingyao; Wang, Xiaotong; Zhang, Miao; Li, Guihua; Gao, Shanmin; Li, Mingyang; Zhang, Yiqing

    2016-02-01

    In this work, vertically-aligned TiO2 nanotube arrays (TiO2 NTs) were grown on Ti substrates via a facile electrochemical anodization method followed by calcinations. Then, Ag-Au alloy nanoparticles and Ag@Au core-shell nanoparticles were deposited on the obtained TiO2 NTs via UV reduction and displacement reaction, respectively. X-ray diffraction, scanning electron microscopy and transmission electron microscopy indicated that Ag-Au alloy nanoparticles and Ag@Au core-shell nanoparticles grew uniformly on the walls of TiO2 NTs. Investigation results from removal of methyl orange (MO) and Cr(IV) ions indicated that the as-prepared bimetal plasmonic photocatalysts exhibited excellent photoelectrocatalytic (PEC) activities. The influences of Ag-Au alloy and core-shell microstructures on PEC properties of TiO2 NTs were investigated and the TiO2 NTs/Ag@Au photocatalyst showed more outstanding PEC removal efficiency than that of TiO2 NTs/Ag-Au due to the regular core-shell microstructure and low recombination of photogenerated electrons and holes. PMID:26555961

  15. Rapid direct conversion of Cu(2-x)Se to CuAgSe nanoplatelets via ion exchange reactions at room temperature.

    Science.gov (United States)

    Moroz, N A; Olvera, A; Willis, G M; Poudeu, P F P

    2015-06-01

    The use of template nanostructures for the creation of photovoltaic and thermoelectric semiconductors is becoming a quickly expanding synthesis strategy. In this work we report a simple two-step process enabling the formation of ternary CuAgSe nanoplatelets with a great degree of control over the composition and shape. Starting with hexagonal nanoplatelets of cubic Cu2-xSe, ternary CuAgSe nanoplatelets were generated through a rapid ion exchange reaction at 300 K using AgNO3 solution. The Cu2-xSe nanoplatelet template and the final CuAgSe nanoplatelets were analyzed by electron microscopy and X-ray diffraction (XRD). It was found that both the low temperature pseudotetragonal and the high temperature cubic forms of CuAgSe phase were created while maintaining the morphology of the Cu2-xSe nanoplatelet template. Thermal and electronic transport measurements of hot-pressed pellets of the synthesized CuAgSe nanoplatelets showed a drastic reduction in the thermal conductivity and a sharp transition from n-type (S = -45 μV K(-1)) to p-type (S = +200 μV K(-1)) semiconducting behavior upon heating above the structural transition from the low temperature orthorhombic to the high temperature super-ionic cubic phase. This simple reaction process utilizing a template nanostructure matrix represents an energy efficient, cost-efficient, and versatile strategy to create interesting materials with lower defect density and superior thermoelectric performance. PMID:25965176

  16. Structure and properties of EuTSb (T = Cu, Pd, Ag, Pt, Au) and YbIrSb

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Trinath; Schellenberg, Inga; Eul, Matthias; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2011-07-01

    The equiatomic antimonides EuTSb (T = Cu, Pd, Ag, Pt, Au) and YbIrSb were synthesized from the elements in sealed tantalum tubes in an induction furnace. The samples were investigated by powder X-ray diffraction and the structures were refined on the basis of single crystal X-ray diffractometer data: ZrBeSi type, P6{sub 3}/mmc, a = 450.7(5), c = 853.2(7) pm, wR2 = 0.032, 273 F{sup 2} values, 8 variables for EuCuSb, a = 474.9(1), c = 829.4(3) pm, wR2 = 0.028, 166 F{sup 2} values, 8 variables for EuAgSb, a = 467.1(2), c = 848.8(3) pm, wR2 = 0.042, 162 F{sup 2} values, 8 variables for EuAuSb, and TiNiSi type, space group Pnma, a = 762.5(3), b = 469.1(1), c = 792.1(1) pm, wR2 = 0.046, 670 F{sup 2} values, 20 variables for EuPdSb, and a = 700.7(1), b = 444.68(8), c = 781.3(1) pm, wR2 = 0.075, 592 F{sup 2} values, 20 variables for YbIrSb. The structures are ordered superstructure variants of the aristotype AlB{sub 2}3 with planar T{sub 3}Sb{sub 3} hexagons in EuTSb (T = Cu, Ag, Au) and puckered T{sub 3}Sb{sub 3} hexagons in EuTSb (T = Pd, Pt) and YbIrSb. TiNiSi type EuPtSb was characterized via powder data: a = 759.8(3), b = 465.4(3), c = 791.4(3) pm. Temperature dependent magnetic susceptibility measurements indicate antiferromagnetic ordering for all compounds. The samples were additionally characterized by {sup 121}Sb and {sup 151}Eu Moessbauer spectra. (orig.)

  17. Hardening mechanism of an Ag-Pd-Cu-Au dental casting alloy

    International Nuclear Information System (INIS)

    Age-hardening behaviour and the related microstructural changes were studied to elucidate the hardening mechanism of an Ag-Pd-Cu-Au dental casting alloy by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) observations and electron probe microanalysis (EPMA). By considering hardness test and XRD results together, it was revealed that the hardness increased during the early stage of phase transformation of α into α1. In the SEM photographs, two phases of matrix and particle-like structures were observed, and the precipitation of element from the matrix progressed during isothermal aging. By SEM observations and EPMA analysis, it could be supposed that the increase in hardness was caused by the diffusion and aggregation of Cu atoms from the Ag-rich α matrix containing Au and Cu in the early stage of age-hardening process, and that the decrease in hardness was caused by the progress of coarsening of Cu-rich lamellar precipitates in the later stage of the age-hardening process. The changes in the Ag-rich matrix caused both the increase and decrease in hardness, and the CuPd phase containing small amounts of Zn and Sn did not contribute to the hardness changes

  18. Preparation of Ag/Cu Janus nanowires: Electrodeposition in track-etched polymer templates

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, X.R. [Henan Key Laboratory of Ion Beam Bioengineering, Physical Engineering College, Zhenzhou University, Zhengzhou 450052 (China); Wang, C.M.; Fu, Q.B. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Jiao, Z.; Wang, W.D.; Qin, G.Y. [Henan Key Laboratory of Ion Beam Bioengineering, Physical Engineering College, Zhenzhou University, Zhengzhou 450052 (China); Xue, J.M., E-mail: jmxue@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China)

    2015-08-01

    Highlights: • In this paper, we introduce a simple method for preparation of Janus nanowires by electrodeposition. • Using ion-track-etched PC polymer templates and commercial PC track-etched membrane templates, Ag/Cu Janus nanowires fabricated by this method all have uniform size. No matter how the holes array in the template, regular or not, the nanowires prepared by this method have similar properties. • By controlling the etching time, the size of the nanowires could be controlled easily and special shape nanowires also can be prepared by this template. • The polymer template is very easy to dissolve thoroughly and has no damage to nanowires almost. It is suitable for the preparation of nanowires suspension. • This method also has better applicability for polymer templates and can be seen as a simple convenient method for the preparation of Ag/Cu Janus nanowires. - Abstract: Bimetal (Janus) nanowire has been widely used as a promising nanoscale motor. In this paper we present a highly controllable method to fabricate Ag/Cu Janus nanowires using track-etched polymer templates. Ag/Cu Janus nanowires with uniform size and stabilized structure have been successfully fabricated by electrodepositing Ag nanowires, and subsequently Cu nanowires in track-etched polymer templates. The pore size of nanopores prepared by this template is uniform and continuously controlled, so aperture of achieved nanowires are uniform and can be regulated. This polymer template can dissolve inorganic solvents that do not react with the nanowires, making it is easy to release the nanowires into solution. The nanopore shape in the track-etched templates is adjustable (e.g. conical), nanowires with more special shapes could be fabricated. Thus, these features make this simple and inexpensive method very suitable for the preparation of Janus nanowire.

  19. Preparation of Ag/Cu Janus nanowires: Electrodeposition in track-etched polymer templates

    International Nuclear Information System (INIS)

    Highlights: • In this paper, we introduce a simple method for preparation of Janus nanowires by electrodeposition. • Using ion-track-etched PC polymer templates and commercial PC track-etched membrane templates, Ag/Cu Janus nanowires fabricated by this method all have uniform size. No matter how the holes array in the template, regular or not, the nanowires prepared by this method have similar properties. • By controlling the etching time, the size of the nanowires could be controlled easily and special shape nanowires also can be prepared by this template. • The polymer template is very easy to dissolve thoroughly and has no damage to nanowires almost. It is suitable for the preparation of nanowires suspension. • This method also has better applicability for polymer templates and can be seen as a simple convenient method for the preparation of Ag/Cu Janus nanowires. - Abstract: Bimetal (Janus) nanowire has been widely used as a promising nanoscale motor. In this paper we present a highly controllable method to fabricate Ag/Cu Janus nanowires using track-etched polymer templates. Ag/Cu Janus nanowires with uniform size and stabilized structure have been successfully fabricated by electrodepositing Ag nanowires, and subsequently Cu nanowires in track-etched polymer templates. The pore size of nanopores prepared by this template is uniform and continuously controlled, so aperture of achieved nanowires are uniform and can be regulated. This polymer template can dissolve inorganic solvents that do not react with the nanowires, making it is easy to release the nanowires into solution. The nanopore shape in the track-etched templates is adjustable (e.g. conical), nanowires with more special shapes could be fabricated. Thus, these features make this simple and inexpensive method very suitable for the preparation of Janus nanowire

  20. Antibacterial and UV protective properties of polyamide fabric impregnated with TiO2/Ag nanoparticles

    Directory of Open Access Journals (Sweden)

    Milošević Milica

    2015-01-01

    Full Text Available The possibility of in situ photoreduction of Ag+ ions using colloidal TiO2 nanoparticles deposited on the surface of polyamide fabric in the presence of amino acid alanine and methyl alcohol is discussed. The presence of TiO2/Ag nanoparticles on the polyamide fabric was confirmed by FESEM and ICP analyses. Antibacterial activity of the fabric was tested against Gram-negative bacterium Escherichia coli and Gram-positive bacterium Staphylococcus aureus. Fabricated TiO2/Ag nanoparticles on the surface of polyamide fabric provided maximum bacterial reduction and thus, excellent antibacterial activity. In spite of silver leaching from the fabric during washing, impregnated polyamide fabric preserved maximum reduction of Escherichia coli colonies. Antibacterial activity against Staphylococcus aureus slightly decreased after ten washing cycles, but still antibacterial activity can be considered as satisfactory. In addition, the presence of TiO2/Ag nanoparticles ensured better UV protection efficiency which belongs to very good UV protection category. [Projekat Ministarstva nauke Republike Srbije, br. 45020 i br. 172056

  1. Preparation of sensitive and recyclable porous Ag/TiO2 composite films for SERS detection

    Science.gov (United States)

    Zhang, Zhengyi; Yu, Jiajie; Yang, Jingying; Lv, Xiang; Wang, Tianhe

    2015-12-01

    Porous Ag/TiO2 composite films were prepared by spin coating of titania on normal glass slides and subsequent photochemical deposition of silver nanoparticles (AgNPs). The films were characterized by XRD and FESEM to reveal micro structural and morphological differences between films obtained under varied conditions. The SERS properties of these films were investigated using aqueous crystal violet (CV) as probe molecules. The results indicate that the content of polyethylene glycol (PEG) and photo-reduction time had significant influences on both the microstructure and SERS performance of Ag/TiO2 films. The highest SERS sensitivity that allowed as low as 10-10 M aqueous CV to be detected, was achieved with the PEG/(C4H9O)4Ti molar ratio being 0.08% and with 30 min of UV irradiation. With this film a linear relationship was established through experiment between SERS intensity and CV concentration from 10-10 to 10-5 M, which could be used as a calibration curve for CV concentration measurement. In addition, the film could be reused as a SERS substrate for up to four times without significantly losing SERS sensitivity if a simple regeneration was followed. It is visualized that the Ag/TiO2 film on glass has potentials for being developed into a practical SERS substrate with high sensitivity and good reusability.

  2. Preparation of nano-Ag/TiO2 thin-film

    Institute of Scientific and Technical Information of China (English)

    PENG Bing; WANG Jia; CHAI Li-yuan; MAO Ai-li; WANG Yun-yan

    2008-01-01

    Steady TiO2 water-sol was prepared by peptization and the effects of pH value, temperature, concentration of colloid and peptizator on sol were investigated. Laser grain analyzer was used to verify nano-particles in the sol. The photocatalytic degradation ratio and antibacterial property of nano-Ag/TiO2 thin-film on ceramics were used as the main index in addition to XRD analysis. The effect of film layers, embedding Ag+, annealing temperature and time on the degradation ratio and antibacterial property was studied. The temperature 30-80 ℃, pH 1.2-2.0, concentrations of 0.05-0.3 mol/L sol and 5% HNO3 would be the optimal parameters for the TiO2 water-sol preparation. The nano-Ag/TiO2 film of three layers with 3% AgNO3 embedded and treated at 350 ℃ for 2 h exhibits good performance. The elementary research on the kinetics of degradation shows that the reactions are on the first order kinetics equation.

  3. SiO2/TiO2/Ag multilayered microspheres: Preparation, characterization, and enhanced infrared radiation property

    Science.gov (United States)

    Ye, Xiaoyun; Cai, Shuguang; Zheng, Chan; Xiao, Xueqing; Hua, Nengbin; Huang, Yanyi

    2015-08-01

    SiO2/TiO2/Ag core-shell multilayered microspheres were successfully synthesized by the combination of anatase of TiO2 modification on the surfaces of SiO2 spheres and subsequent Ag nanoparticles deposition and Ag shell growth with face-centered cubic (fcc) Ag. The composites were characterized by TEM, FT-IR, UV-vis, Raman spectroscopy and XRD, respectively. The infrared emissivity values during 8-14 μm wavelengths of the composites were measured. The results revealed that TiO2 thin layers with the thickness of ∼10 nm were coated onto the SiO2 spheres of ∼220 nm in diameter. The thickness of the TiO2 layers was controlled by varying the amount of TBOT precursor. Homogeneous Ag nanoparticles of ∼20 nm in size were successfully deposited by ultrasound on the surfaces of SiO2/TiO2 composites, followed by complete covering of Ag shell. The infrared emissivity value of the SiO2/TiO2 composites was decreased than that of pure SiO2. Moreover, the introduction of the Ag brought the remarkably lower infrared emissivity value of the SiO2/TiO2/Ag multilayered microspheres with the lowest value down to 0.424. Strong chemical effects in the interface of SiO2/TiO2 core-shell composites and high reflection performance of the metal Ag are two decisive factors for the improved infrared radiation performance of the SiO2/TiO2/Ag multilayered microspheres.

  4. Nanostructured Ti-Fe2O3/Cu2O heterojunction photoelectrode for efficient hydrogen production

    International Nuclear Information System (INIS)

    Nanostructured thin films of pristine Fe2O3, Ti-doped Fe2O3, Cu2O, and Fe2O3/Cu2O, and Ti-doped Fe2O3/Cu2O heterojunction were deposited on tin-doped indium oxide (Sn:In2O3) glass substrate using spray pyrolysis method. Ti doping is done to improve photoelectric conversion efficiency and electrical conductivity of hematite thin films. Further enhanced photocurrent is achieved for Ti-Fe2O3/Cu2O heterojunction electrodes. All samples were characterized using X-ray diffractometry, scanning electron microscopy, atomic force microscopy, and UV-Vis spectrometry. Photoelectrochemical properties were also investigated in a three-electrode cell system. UV-Vis absorption spectrum for pristine Fe2O3, Ti-Fe2O3, Cu2O, Fe2O3/Cu2O, and Ti-Fe2O3/Cu2O heterojunction thin films exhibited absorption in visible region. Nanostructured thin films as prepared were used as photoelectrode in the photoelectrochemical cell for water splitting reaction. Maximum photocurrent density of 2.60 mA/cm2 at 0.95 V/SCE was exhibited by 454 nm thick Ti-Fe2O3/Cu2O heterojunction photoelectrode. Increased photocurrent density and enhanced incident photon-to-electron conversion efficiency, offered by the heterojunction thin films may be attributed to improved conductivity and efficient separation of the photogenerated charge carriers at the Ti-Fe2O3/Cu2O interface. - Highlights: • Heterojunction thin films were deposited using spray pyrolysis techniques. • Titanium doping in Fe2O3 played a significant role in PEC response. • Ti-Fe2O3/Cu2O heterojunction shows the absorption in visible range. • Improved charge separation and enhanced PEC response were achieved in Ti-Fe2O3/Cu2O

  5. Photocatalytic properties of porous C-doped TiO2 and Ag/C-doped TiO2 nanomaterials by eggshell membrane templating

    International Nuclear Information System (INIS)

    Porous organic carbon-doped titania (C-TiO2) nanomaterials and their composites with Ag nanoparticles (Ag/C-TiO2) were synthesized by an eggshell membrane templating method, and their structural and photocatalytic properties were systematically characterized. These nanomaterials, exhibiting a macroscopic morphology of a thin film, are composed of interwoven tubes, and the tube wall consists of nanocrystals. The doped organic carbon was composed of the active carbon and carbonate species, which could form a layer around the surface of TiO2 nanoparticles, while the silver was incorporated into Ag/C-TiO2 composites as separated Ag nanoparticles. The degradation of methylene blue under visible light irradiation was employed to evaluate the photocatalytic activity of these as-prepared TiO2-based materials. Both C-TiO2 and Ag/C-TiO2 nanomaterials showed higher photocatalytic activity than pure TiO2 material-commercial Degussa P25. These results can be accounted for the coupling effect of the incorporation of carbon species and Ag nanoparticles.

  6. Phases and phase equilibria in the quaternary system Ti-Cu-Al-N at 850 C

    Energy Technology Data Exchange (ETDEWEB)

    Durlu, N. [Vienna Univ. (Austria); Gruber, U. [Vienna Univ. (Austria); Pietzka, M.A. [Vienna Univ. (Austria); Schmidt, H. [Vienna Univ. (Austria); Schuster, J.C. [Vienna Univ. (Austria)

    1997-05-01

    Phase equilibria in the quaternary system Ti-Cu-Al-N are investigated using XRD, metallography and EDX, yielding the observation of 18 four phase spaces of the 850 C isotherm. In the ternary boundary systems Ti-Cu-Al and Ti-Al-N, all previously reported phases are confirmed, but several tielines are newly determined. In the system Ti-N, the new ternary phase Ti{sub 3}CuN dominates most phase fields. Based on thermochemical data of the binary boundary systems and the newly investigated or re-investigated phase equilibria of the ternary boundary systems, a set of Gibbs energies for the solid phases occuring in the quaternary system is derived, which is used in combination with the quaternary experimental data to derive a large section of the isotherm for Ti-Cu-Al-N at 850 C. The quaternary {eta}-phase (Ti, Cu, Al){sub 6}N having the composition Ti{sub 3}Cu{sub 2}Al{sub 1}N{sub 0.8} is found to be the only stable quaternary phase of this system. Several {eta}-phases isotypic to Ti{sub 3}Cu{sub 2}Al{sub 1}N{sub 0.8} are synthesized to explore the crystal chemistry effects of substitutions on different crystallographic sites. (orig.)

  7. Investigation on the interaction of nanoAg with Cu-Zn SOD.

    Science.gov (United States)

    Zhang, Bin; Yu, Lei; Zhang, Ruijing; Liu, Yang; Liu, Rutao

    2015-12-01

    Silver nanoparticles (nanoAg) are used more and more widely, particularly because of their antimicrobial properties. The effect of exposure to nanoAg on the structure of superoxide dismutase (SOD) was thoroughly investigated using fluorescence measurements, synchronous fluorescence spectroscopy, steady-state and time-resolved fluorescence quenching measurements, UV/Vis absorption spectroscopy, resonance light scattering (RLS), circular dichroism (CD), isothermal titration calorimetry (ITC) and high-resolution transmission electron microscopy (HRTEM). Through van der Waal's force, nanoAg interacted with Cu-Zn SOD and influenced the active site by inducing structural changes, which influenced the function of SOD. The fluorescence studies show that both static and dynamic quenching processes occur. This paper provides reference data for toxicological studies of nanoAg, which are important in the future development of nanotechnology. PMID:25754791

  8. Reduced graphene oxide and Ag wrapped TiO2 photocatalyst for enhanced visible light photocatalysis

    International Nuclear Information System (INIS)

    A well-organised reduced graphene oxide (RGO) and silver (Ag) wrapped TiO2 nano-hybrid was successfully achieved through a facile and easy route. The inherent characteristics of the synthesized RGO-Ag/TiO2 were revealed through crystalline phase, morphology, chemical composition, Raman scattering, UV-visible absorption, and photoluminescence analyses. The adopted synthesis route significantly controlled the uniform formation of silver nanoparticles and contributed for the absorption of light in the visible spectrum through localized surface plasmon resonance effects. The wrapped RGO nanosheets triggered the electron mobility and promoted visible light shift towards red spectrum. The accomplishment of synergised effect of RGO and Ag well degraded Bisphenol A under visible light irradiation with a removal efficiency of 61.9%

  9. Aerosol deposition of (Cu,Ti) substituted bismuth vanadate films

    International Nuclear Information System (INIS)

    Bismuth vanadate, Bi4V2O11, and related compounds with various metal (Me) substitutions, Bi4(MexV1−x)2O11−δ, show some of the highest ionic conductivities among the known solid oxide electrolytes. Films of Cu and Ti substituted bismuth vanadate were prepared by an aerosol deposition method, a spray coating process also described as room temperature impact consolidation. Resultant films, several microns in thickness, were dense with good adhesion to the substrate. Scanning electron microscopy and high temperature X-ray diffraction were used to monitor the effects of temperature on the structure and microstructure of the film. The particle size remained nano-scale while microstrain decreased rapidly up to 500 °C, above which coarsening and texturing increased rapidly. Impedance measurements of films deposited on inter-digital electrodes revealed an annealing effect on the ionic conductivity, with the conductivity exceeding that of a screen printed film, and approaching that of bulk ceramic. - Highlights: • Cu and Ti doped bismuth vanadate films were prepared by aerosol deposition (AD). • Dense 3–5 μm thick films were deposited on alumina, silicon and gold electrodes. • Annealing of the AD-layer increases the conductivity by 1.5 orders of magnitude. • Effect of temperature on structure and microstructure was investigated

  10. Aerosol deposition of (Cu,Ti) substituted bismuth vanadate films

    Energy Technology Data Exchange (ETDEWEB)

    Exner, Jörg, E-mail: Functional.Materials@Uni-Bayreuth.de [University of Bayreuth, Department of Functional Materials, Universitätsstraße 30, 95440 Bayreuth (Germany); Fuierer, Paul [Materials and Metallurgical Engineering Department, New Mexico Institute of Mining and Technology, Socorro, NM 87801 (United States); Moos, Ralf [University of Bayreuth, Department of Functional Materials, Universitätsstraße 30, 95440 Bayreuth (Germany)

    2014-12-31

    Bismuth vanadate, Bi{sub 4}V{sub 2}O{sub 11}, and related compounds with various metal (Me) substitutions, Bi{sub 4}(Me{sub x}V{sub 1−x}){sub 2}O{sub 11−δ}, show some of the highest ionic conductivities among the known solid oxide electrolytes. Films of Cu and Ti substituted bismuth vanadate were prepared by an aerosol deposition method, a spray coating process also described as room temperature impact consolidation. Resultant films, several microns in thickness, were dense with good adhesion to the substrate. Scanning electron microscopy and high temperature X-ray diffraction were used to monitor the effects of temperature on the structure and microstructure of the film. The particle size remained nano-scale while microstrain decreased rapidly up to 500 °C, above which coarsening and texturing increased rapidly. Impedance measurements of films deposited on inter-digital electrodes revealed an annealing effect on the ionic conductivity, with the conductivity exceeding that of a screen printed film, and approaching that of bulk ceramic. - Highlights: • Cu and Ti doped bismuth vanadate films were prepared by aerosol deposition (AD). • Dense 3–5 μm thick films were deposited on alumina, silicon and gold electrodes. • Annealing of the AD-layer increases the conductivity by 1.5 orders of magnitude. • Effect of temperature on structure and microstructure was investigated.

  11. Structural studies of Nd$_{1.85}$Ce$_{0.15}$CuO$_{4}$ $+$ Ag superconducting system

    Indian Academy of Sciences (India)

    N RADHIKESH RAVEENDRAN; A K SINHA; R RAJARAMAN; M PREMILA; E P AMALADASS; K VINOD; J JANAKI; S KALAVATHI; AWADHESH MANI

    2016-06-01

    We have studied for the first time the effect of Ag addition (0–15 wt%) to the superconducting system, Nd$_{1.85}$Ce$_{0.15}$CuO$_{4}$, on its crystal structure and local structural features, using synchrotron X-ray diffraction(SXRD) and Raman spectroscopy, respectively. SXRD and subsequent Rietveld refinement studies on powders of Nd$_{1.85}$Ce$_{0.15}$CuO$_4$ $+$ Ag system indicate a small but significant change in lattice parameter upon Ag addition, showing evidence for possible incorporation of Ag to the extent of $\\sim$1 wt%. Raman spectroscopic studies indicate that the parent structure of Nd$_{1.85}$Ce$_{0.15}CuO$_{4}$ remains unaffected with no major local structural changes on doping with silver. However, all Raman modes show minor phonon hardening upon Ag addition, which is consistent with the unit cell volume reduction as is observed in XRD. A systematic bleaching out of the apical oxygen defect mode was also observed with increased Ag addition. Polarized Raman measurements helped to identify the asymmetric nature of the B1g Raman mode. X-ray diffraction studies on pellets of Nd$_{1.85}$Ce$_{0.15}CuO$_4$ $+$ Ag system further indicate a randomization of preferred orientation upon Ag addition. The superconductivity of the Nd$_{1.85}$Ce$_{0.15}$CuO$_4$ $+$ Ag system has been well characterized for all the compositions studied.

  12. Structure, phase composition and microhardness of vacuum-arc multilayered Ti/Al, Ti/Cu, Ti/Fe, Ti/Zr nano-structures with different periods

    International Nuclear Information System (INIS)

    Highlights: • Multilayer coatings of Ti/Fe, Ti/Al, Ti/Cu and Ti/Zr are generated. • Microstructure and morphology of the different systems are investigated. • XR diffraction analysis was performed to investigate phases composition. • Effects of inter metallic phases on microhardess are investigated. • Correlations between parameters and layer thickness are outlined. - Abstract: The microstructure, phase composition and microhardness of multilayered Ti/Al, Ti/Cu, Ti/Fe and Ti/Zr condensates produced on stainless steel substrates via vacuum-arc evaporation of pure metals were studied. The sublayer periods (Λ) were regulated in the range 80–850 nm by varying the vacuum discharge current and the duration of the successive depositions of metallic plasma onto the substrates while maintaining the total deposition time constant. The regularity of the obtained nanostructures was investigated by scanning and transmission electron microscopy while phase compositions were identified with X-ray diffraction (XRD) analysis in order to evidence the presence of interdiffusion and the amount of intermetallics. Condensates cross sections were mechanically characterized by means of microhardness tests. Measurements were correlated to the periods and to the presence of intermetallics

  13. Thermomechanical processing of CuTi4 alloy

    Directory of Open Access Journals (Sweden)

    Z. Rdzawski

    2010-09-01

    Full Text Available Purpose: One of the reasons behind the interest in copper titanium alloys was development of new materials to substitute copper beryllium alloys. The reason for selecting that material for studies was that in the early stages of decomposition of CuTi4 alloy a spinodal transformation takes place and ordering processes begin. Proper selection of heat treatment and plastic working conditions provides possibilities to produce very wide range of sets of properties by formation of the required alloy microstructure. Therefore the main objective of the study was to capture the changes in precipitation kinetics, especially in the relations between supersaturation and ageing or between supersaturaion, cold deformation and ageing in connection to the changes in microstructure and functional properties (mainly changes in hardness and electrical conductivity.Design/methodology/approach: Melting of the charge material was conducted in medium-frequency induction furnace, in a graphite crucible. The melted material after bath preparation was poured into a cast iron ingot mould (with graphite grease applied on the inside of dimensions 35 x 120 x 250 mm. The ingots after casting were peeled. The treated ingots were heated in resistance furnace at 900ºC for 1.5 hour and rolled down on a reversible two-high mill.Findings: Decomposition of supersaturated solid solution in that alloy is similar to the alloys produced in laboratory scale. The observed differences in microstructure after supersaturation were related to the presence of undissolved Ti particles and increased segregation of titanium distribution in copper matrix including microareas of individual grains. The mentioned factors influence the mechanism and kinetics of precipitation and subsequently the produced wide ranges of functional properties of the alloy.Research limitations/implications: Cold deformation (50% reduction of the alloy after supersaturation changes the mechanism and kinetics of

  14. Highly selective and sensitive reversible sensor for Cu (II) detection based on hollow TiO2 spheres modified by fluorescein hydrozine-3,6-diacetic acid

    International Nuclear Information System (INIS)

    ABSTRACT: We report a novel electrochemical sensor for the sensitive detection of Cu(II) ions based on hollow TiO2 spheres modified by fluorescein hydrozine-3,6-diacetic acid (FH). Herein, hollow TiO2 spheres were synthesized via the hydrothermal method with the carbon spheres as the template then modified by (3-aminopropyl) trimethoxysilane (APTMS) to form the amino group-modified TiO2 spheres (TiO2–APTMS). Simultaneously, FH was activated by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride/N-hydroxysuccinimide, in which the carboxyl groups were changed to active ester groups. Consequently, TiO2–APTMS spheres could be modified by FH with the activated ester groups via the bonding of amide groups to produce the composite electrode with TiO2 and FH (Au–TiO2–FH). The resulting Au–TiO2–FH was used to develop the electrochemical sensor for the highly sensitive detection of Cu2+ in aqueous solution because of the coordination between Cu2+ and FH, the whole process of which was determined via electrochemical impedance spectroscopy. The results showed that a detection limit of 4.29 pM of the developed sensor within the range from 5 pM to 1 μM was obtained. Furthermore, the interference from other metal ions, such as K+, Na+, Ag+, Ni2+, Mn2+, Zn2+, Mg2+, and Fe3+, associated with Cu2+ analysis could be effectively inhibited. Most importantly, the developed electrochemical sensor could be reproduced and degraded by UV light irradiation because of the light degradation ability of TiO2 toward FH. This novel sensor could also be used to detect other heavy metal ions when TiO2 spheres are modified by the relative FH

  15. Preparation and self-sterilizing properties of Ag@TiO{sub 2}–styrene–acrylic complex coatings

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xiang-dong; Chen, Feng; Yang, Jin-tao, E-mail: yangjt@zjut.edu.cn; Yan, Xiao-hui; Zhong, Ming-qiang, E-mail: zhongmingqiang@hotmail.com

    2013-04-01

    In this study, we report a simple and cost-effective method for self-sterilized complex coatings obtained by Ag@TiO{sub 2} particle incorporation into styrene–acrylic latex. The Ag@TiO{sub 2} particles were prepared via a coupling agent modification process. The composite latices characterized by transmission electron microscopy (TEM) study were highly homogeneous at the nanometric scale, and the Ag@TiO{sub 2} particles were well dispersed and exhibited an intimate contact between both the organic and inorganic components. The Ag@TiO{sub 2} nanoparticles significantly enhanced the absorption in the visible region and engendered a good heat-insulating effect of the complex coatings. Moreover, the Ag@TiO{sub 2} nanoparticle incorporation into this polymer matrix renders self-sterilized nanocomposite materials upon light excitation, which are tested against Escherichia coli and Staphylococcus aureus. The complex coatings display an impressive performance in the killing of all micro-organisms with a maximum for a Ag@TiO{sub 2} loading concentration of 2–5 wt.%. The weathering endurance of the complex coating was also measured. - Highlights: ► We prepared Ag@TiO{sub 2}–styrene–acrylic complex latex in one pot. ► Good antibacterial performances of complex coatings were observed. ► The complex coating was resistant to weathering after 48 h. ► The complex coating exhibits good heat-insulating effect.

  16. Preparation and self-sterilizing properties of Ag@TiO2–styrene–acrylic complex coatings

    International Nuclear Information System (INIS)

    In this study, we report a simple and cost-effective method for self-sterilized complex coatings obtained by Ag@TiO2 particle incorporation into styrene–acrylic latex. The Ag@TiO2 particles were prepared via a coupling agent modification process. The composite latices characterized by transmission electron microscopy (TEM) study were highly homogeneous at the nanometric scale, and the Ag@TiO2 particles were well dispersed and exhibited an intimate contact between both the organic and inorganic components. The Ag@TiO2 nanoparticles significantly enhanced the absorption in the visible region and engendered a good heat-insulating effect of the complex coatings. Moreover, the Ag@TiO2 nanoparticle incorporation into this polymer matrix renders self-sterilized nanocomposite materials upon light excitation, which are tested against Escherichia coli and Staphylococcus aureus. The complex coatings display an impressive performance in the killing of all micro-organisms with a maximum for a Ag@TiO2 loading concentration of 2–5 wt.%. The weathering endurance of the complex coating was also measured. - Highlights: ► We prepared Ag@TiO2–styrene–acrylic complex latex in one pot. ► Good antibacterial performances of complex coatings were observed. ► The complex coating was resistant to weathering after 48 h. ► The complex coating exhibits good heat-insulating effect

  17. Photocatalytic Bactericidal Efficiency of Ag Doped TiO2/Fe3O4 on Fish Pathogens under Visible Light

    Directory of Open Access Journals (Sweden)

    Ekkachai Kanchanatip

    2014-01-01

    Full Text Available This research evaluates photocatalytic bactericidal efficiencies of Ag-TiO2/Fe3O4 in visible light using target pollutants that include Aeromonas hydrophila, Edwardsiella tarda, and Photobacterium damselae subsp. piscicida. The investigation started with Ag-TiO2/Fe3O4 synthesis and calcination followed by a series of product tests that include the examination of crystallite phase, light absorption, element composition morphology, and magnetic properties. The results of the experiment indicate that Ag and Fe3O4 significantly enhanced the light absorption capacity of TiO2 in the entire visible light range. The Ag-TiO2/Fe3O4 prepared in this study displays significantly enhanced visible light absorption and narrowed band gap energy. The magnetic property of Ag-TiO2/Fe3O4 made it easy for retrieval using a permanent magnet bar. The photocatalytic activity of Ag-TiO2/Fe3O4 remains above 85% after three application cycles, which indicates high and favorable efficiency in bactericidal evaluation. The experiments have proved that the Ag-TiO2/Fe3O4 magnetic photocatalyst is a promising photocatalyst for antibacterial application under visible light.

  18. Enhanced thermal stability under DC electrical conductivity retention and visible light activity of Ag/TiO₂@polyaniline nanocomposite film.

    Science.gov (United States)

    Ansari, Mohd Omaish; Khan, Mohammad Mansoob; Ansari, Sajid Ali; Raju, Kati; Lee, Jintae; Cho, Moo Hwan

    2014-06-11

    The development of organic-inorganic photoactive materials has resulted in significant advancements in heterogeneous visible light photocatalysis. This paper reports the synthesis of visible light-active Ag/TiO2@Pani nanocomposite film via a simple biogenic-chemical route. Electrically conducting Ag/TiO2@Pani nanocomposites were prepared by incorporating Ag/TiO2 in N-methyl-2-pyrrolidone solution of polyaniline (Pani), followed by the preparation of Ag/TiO2@Pani nanocomposite film using solution casting technique. The synthesized Ag/TiO2@Pani nanocomposite was confirmed by UV-visible spectroscopy, photoluminescence spectroscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The Ag/TiO2@Pani nanocomposite film showed superior activity towards the photodegradation of methylene blue under visible light compared to Pani film, even after repeated use. Studies on the thermoelectrical behavior by DC electrical conductivity retention under cyclic aging techniques showed that the Ag/TiO2@Pani nanocomposite film possessed a high combination of electrical conductivity and thermal stability. Because of its better thermoelectric performance and photodegradation properties, such materials might be a suitable advancement in the field of smart materials in near future. PMID:24836114

  19. Room-temperature synthesis of (Ag,Cu)2S hollow spheres by cation exchange and their optical properties

    International Nuclear Information System (INIS)

    Research highlights: → Hollow (Ag,Cu)2S microspheres with diameter of 700 nm to 1 μm were prepared with CuS hollow spheres as templates at room temperature. → The shell was composed of nanoparticles. → The absorption of hollow (Ag,Cu)2S spheres was strong in ultraviolet and infrared region but weak in visible region. - Abstract: Hollow (Ag,Cu)2S microspheres were prepared with spherical aggregates of CuS nanoparticles as templates at room temperature. The products were characterized using transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The result showed that when the molar ratio of CuS to Ag+ was 2:1, the obtained product was hollow microspheres with diameter of 700 nm to 1 μm. The shell of the hollow spheres was composed of (Ag,Cu)2S nanoparticles. The absorption of hollow (Ag,Cu)2S spheres was strong in ultraviolet and infrared region but weak in visible region. It will be valuable optical materials for selective absorption or transmission.

  20. Fabrication of AgAu alloy-TiO2 core-shell nanoparticles and their photocatalytic properties

    Science.gov (United States)

    Zhang, Xiao-yu; Yuan, Shu-long; Yuan, Yu-zhen; Li, Xue

    2015-01-01

    In this paper, for improving the photocatalytic efficiency of titania (TiO2) nanoparticles (NPs), AgAu alloy-TiO2 core-shell NPs are fabricated via a sol-gel (SG) process in the presence of AgAu alloy NPs with block copolymer shells as templates. The photocatalytic activities of the AgAu-TiO2 NPs on the photodecomposition of methylene blue (MB) are investigated. The AgAu-TiO2 composite NPs coated with 5.0% titania related to block copolymers show higher photocatalytic activity than the other samples in which the titania contents are larger than 5.0%. The results indicate that the increase of the thickness of the TiO2 shell leads to the decrease of the photocatalytic activity.

  1. Investigation of Ag-TiO2 nanostructures photocatalytic properties prepared by modified dip coating method

    Science.gov (United States)

    AlArfaj, Esam

    2016-05-01

    In this article, titanium dioxide and silver nanostructures were deposited on glass substrates using modified sol-gel methods and dip-coating technique. The films were characterised chemically and physically using different techniques (TLC, UV-Vis and XRD) and tested for environmental applications regarding degradation of aromatic hydrocarbons. The photocatalytic activity of the TiO2 nanostructures is tested with different small concentrations of phenol in water and reaction mechanisms discussed. Considerable enhancement is observed in the photodegradation activity of Ag-modified (3 wt.%) TiO2 compared to unmodified TiO2 nanostructures for phenol concentrations within the pseudo-first-order Langmuir-Hinshelwood (LH) model for reaction kinetics. The pseudo-first-order global degradation rate constant increased from <0.005 min-1 for TiO2 to 0.013 min-1 for 3 mol% Ag-modified TiO2. The enhancement is attributed to the incorporation of Ag which promotes the generation of reactive oxygen species and increases the carrier recombination life-time. In addition, Ag has been observed to extend the absorption to the visible region by its surface plasmon resonances and to suppress the anatase-rutile phase transformation. Moreover, TiO2 grain size prepared was found to be 10 nm which maximises the active surface area. For phenol initial concentrations as low as 0.0002 M, saturation trend in the degradation process occurred at 0.00014 M and the reaction rate can be fitted with half-order LH kinetics.

  2. Ti microalloying effect on corrosion resistance and thermal stability of CuZr-based bulk metallic glasses

    International Nuclear Information System (INIS)

    Bulk metallic glasses (BMGs) of (Cu37.6Zr46Ag8.4Al8)100-xTix with x = 0, 1, 2 and 4 at.% were prepared by copper mold casting. The corrosion resistance of the CuZr-based BMGs with different Ti contents was carefully examined by potentiodynamic polarization tests in 1N NaOH, 1N H2SO4, 1N H2SO4 + 0.01N NaCl and 1N H2SO4 + 0.1N NaCl solutions, respectively. The BMGs exhibit excellent corrosion resistance in 1N NaOH and 1N H2SO4 solutions. Ti addition greatly improves the newly developed BMGs' corrosion resistance in both H+ and Cl- ions containing solutions. The influence of Ti addition on glass forming ability (GFA) and thermal stability was investigated by X-ray diffraction and differential scanning calorimetry. It is found that the alloys still have large GFA although thermal stability is slightly deteriorated with Ti addition.

  3. Synthesis of surface plasmon resonance (SPR) triggered Ag/TiO2 photocatalyst for degradation of endocrine disturbing compounds

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Ag/TiO2 was synthesized with aid of natural photon stimulated photoreduction. • Deposited Ag prompted well the LSPRs, Schottky barrier for visible light utilization. • Photocatalytic activity was evaluated by degrading EDCs under visible light. • 3.0 wt% Ag/TiO2 resulted with good photocatalytic efficiency over others. - Abstract: Surface deposition of silver nanoparticles (Ag NPs) onto the 100% anatase titania (Ag/TiO2) for evolution of surface plasmon resonance (SPR) was achieved sustainably with the assistance of solar energy. The preparation resulted in Ag/TiO2 photocatalyst with varied Ag depositions (0.5 wt%, 1.0 wt%, 3.0 wt% and 5.0 wt%). All obtained photocatalysts were characterized for the evolution of SPR via crystalline phase analysis, morphology, lattice fringes, surface area and pore size characteristics, chemical composition with chemical and electronic state, Raman scattering, optical and photoluminescence properties. The deposition of synthesized Ag NPs exhibited high uniformity and homogeneity and laid pathway for effective utilization of the visible region of electromagnetic spectrum through SPR. The depositions also lead for suppressing recombination rates of electron–hole. The photocatalytic evaluation was carried out by adopting two different class of endocrine disturbing compound (EDC) i.e., amoxicillin (pharmaceutical) and 2,4-dichlorophenol (pesticide) excited with artificial visible light source. Ag/TiO2 with Ag > 0.5 wt% exhibited significant degradation efficiency for both amoxicillin and 2,4-dichlorophenol. Thus synthesized Ag/TiO2 revealed the implication of plasmonics on TiO2 for the enhanced visible light photocatalytic activity

  4. Synthesis of surface plasmon resonance (SPR) triggered Ag/TiO{sub 2} photocatalyst for degradation of endocrine disturbing compounds

    Energy Technology Data Exchange (ETDEWEB)

    Leong, Kah Hon; Gan, Bee Ling; Ibrahim, Shaliza [Environmental Engineering Laboratory, Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Saravanan, Pichiah, E-mail: saravananpichiah@um.edu.my [Environmental Engineering Laboratory, Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Nanotechnology and Catalysis Research Center (NANOCAT), University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2014-11-15

    Graphical abstract: - Highlights: • Ag/TiO{sub 2} was synthesized with aid of natural photon stimulated photoreduction. • Deposited Ag prompted well the LSPRs, Schottky barrier for visible light utilization. • Photocatalytic activity was evaluated by degrading EDCs under visible light. • 3.0 wt% Ag/TiO{sub 2} resulted with good photocatalytic efficiency over others. - Abstract: Surface deposition of silver nanoparticles (Ag NPs) onto the 100% anatase titania (Ag/TiO{sub 2}) for evolution of surface plasmon resonance (SPR) was achieved sustainably with the assistance of solar energy. The preparation resulted in Ag/TiO{sub 2} photocatalyst with varied Ag depositions (0.5 wt%, 1.0 wt%, 3.0 wt% and 5.0 wt%). All obtained photocatalysts were characterized for the evolution of SPR via crystalline phase analysis, morphology, lattice fringes, surface area and pore size characteristics, chemical composition with chemical and electronic state, Raman scattering, optical and photoluminescence properties. The deposition of synthesized Ag NPs exhibited high uniformity and homogeneity and laid pathway for effective utilization of the visible region of electromagnetic spectrum through SPR. The depositions also lead for suppressing recombination rates of electron–hole. The photocatalytic evaluation was carried out by adopting two different class of endocrine disturbing compound (EDC) i.e., amoxicillin (pharmaceutical) and 2,4-dichlorophenol (pesticide) excited with artificial visible light source. Ag/TiO{sub 2} with Ag > 0.5 wt% exhibited significant degradation efficiency for both amoxicillin and 2,4-dichlorophenol. Thus synthesized Ag/TiO{sub 2} revealed the implication of plasmonics on TiO{sub 2} for the enhanced visible light photocatalytic activity.

  5. Single-wall carbon nanotube (SWCNT) functionalized Sn-Ag-Cu lead-free composite solders

    International Nuclear Information System (INIS)

    Sn-3.8Ag-0.7Cu-based composite solders functionalized with single-wall carbon nanotubes (SWCNTs) with various weight proportions ranging from 0.01 to 1 wt% were successfully produced. The microstuctural, melting and mechanical properties of Sn-3.8Ag-0.7Cu-based composite solders were evaluated as a function of different wt% of SWCNT addition. The microstructures of the composite specimens were studied by means of field-emission scanning electron microscope (FE-SEM). It was observed that SWCNTs were homogeneously distributed at the edges of Ag3Sn compounds that are distributed evenly in the β-Sn solder matrix. Energy dispersion X-ray (EDX) analysis method was employed to reveal the presence of the phases existed in the solder composites. The mechanical properties of the composite solders were evaluated by Vickers-microhardness measurements and tensile tests performed at room temperature. The different wt% and addition of SWCNTs to Sn-3.8Ag-0.7Cu produced a dramatic increase in tensile strength, hardness, and better melting characteristics. A slight decrease in elongation to failure was observed. FE-SEM observations of the fracture surface, revealed the overall failure mechanism as the ductile manner of failure

  6. Ag-bridged Ag{sub 2}O nanowire network/TiO{sub 2} nanotube array p–n heterojunction as a highly efficient and stable visible light photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chengbin, E-mail: chem_cbliu@hnu.edu.cn [Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063 (China); State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Cao, Chenghao [State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Luo, Xubiao [Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063 (China); Luo, Shenglian [Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063 (China); State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China)

    2015-03-21

    Graphical abstract: A unique Ag-bridged Ag{sub 2}O nanowire network/TiO{sub 2} nanotube array p–n heterojunction was fabricated by simple electrochemical method. The heterostructures exhibit high photocatalytic activity and excellent recycling performance. - Highlights: • Ag-bridged Ag{sub 2}O nanowire network self-stability structure. • Ag{sub 2}O nanowire network/TiO{sub 2} nanotube p–n heterojunction. • High visible light photocatalytic activity. • Highly stable recycling performance. - Abstract: A unique Ag-bridged Ag{sub 2}O nanowire network/TiO{sub 2} nanotube array p–n heterojunction (Ag–Ag{sub 2}O/TiO{sub 2} NT) was fabricated by simple electrochemical method. Ag nanoparticles were firstly electrochemically deposited onto the surface of TiO{sub 2} NT and then were partly oxidized to Ag{sub 2}O nanowires while the rest of Ag mother nanoparticles were located at the junctions of Ag{sub 2}O nanowire network. The Ag–Ag{sub 2}O/TiO{sub 2} NT heterostructure exhibited strong visible-light response, effective separation of photogenerated carriers, and high adsorption capacity. The integration of Ag–Ag{sub 2}O self-stability structure and p–n heterojunction permitted high and stable photocatalytic activity of Ag–Ag{sub 2}O/TiO{sub 2} NT heterostructure photocatalyst. Under 140-min visible light irradiation, the photocatalytic removal efficiency of both dye acid orange 7 (AO7) and industrial chemical p-nitrophenol (PNP) over Ag–Ag{sub 2}O/TiO{sub 2} NT reached nearly 100% much higher than 17% for AO7 or 13% for PNP over bare TiO{sub 2} NT. After 5 successive cycles under 600-min simulated solar light irradiation, Ag–Ag{sub 2}O/TiO{sub 2} NT remained highly stable photocatalytic activity.

  7. Dielectric properties of CaCu2.9Co0.1Ti4O12 and CaCu3Ti3.9Co0.1O12 ceramics synthesized by semi-wet route

    Indian Academy of Sciences (India)

    K D Mandal; Alok Kumar Rai; Laxman Singh; Om Parkash

    2012-06-01

    The effect of Co+2 doping on Cu+2 and Ti+4 sites in calcium copper titanate, CaCu3Ti4O12, has been examined. The doped compositions, CaCu3−CoTi4O12 and CaCu3Ti4−CoO12 ( = 0.10) ceramics, were prepared by novel semi-wet route. In this method, calcium, copper and cobalt salts were taken in solution form and TiO2 was used in solid form. XRD analysis confirmed the formation of single-phase materials. Structure of CaCu3Ti4O12 does not change on doping with cobalt either on Cu-site or Ti-site and it remains cubic. Scanning electron micrographs (SEM) show average grain size of CaCu2.9Co0.1Ti4O12 to be larger than CaCu3Ti3.9Co0.1O12 ceramic. Energy dispersive X-ray spectroscopy (EDX) studies confined the purity of parent and Co-doped CaCu3Ti4O12 ceramics. Dielectric constant (r) and dielectric loss (tan ) of CaCu2.9Co0.1Ti4O12 is comparatively higher than that of CaCu3Ti3.9Co0.1O12 ceramic at all measured frequencies and temperatures.

  8. Cu/TiO2 thin films prepared by reactive RF magnetron sputtering

    Science.gov (United States)

    Sreedhar, M.; Reddy, I. Neelakanta; Bera, Parthasarathi; Ramachandran, D.; Gobi Saravanan, K.; Rabel, Arul Maximus; Anandan, C.; Kuppusami, P.; Brijitta, J.

    2015-08-01

    Cu/TiO2 thin films were deposited on glass substrates by reactive RF magnetron sputtering technique. Crystalline structure, surface morphology and electronic structure were studied using X-ray diffraction (XRD), field emission scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy (XPS). Transmittance and absorptance of these films were characterized by UV-Vis spectroscopy. XRD patterns demonstrate that TiO2 films deposited on glass substrate at 300 °C are observed to be in pure anatase phase, whereas Cu/TiO2 films are amorphous in nature at 300 °C substrate temperature. The crystallinity of Cu/TiO2 thin films decreases with increasing the dopant concentrations of Cu in TiO2 films. XPS studies show that Cu is in +2 oxidation state in all films. The optical band gap of Cu/TiO2 films decreases from ~3.3 to ~2.0 eV with the increase in the copper concentration. Further, antimicrobial studies of Cu/TiO2 films with ~3.9 at.% Cu exhibit high transmittance and best antimicrobial activity against E. coli and S. aureus compared to other doped films.

  9. The isothermal section at 923 K of the Co-Cu-Ti ternary system measured by using diffusion triple

    International Nuclear Information System (INIS)

    The isothermal section at 923 K in the Co-Cu-Ti system was experimentally studied by using the diffusion triple technique together with scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). High solubility of Cu, up to 22.5 at.% (substituting Co) in CoTi was observed at this temperature; and the solubility of Co (substituting Cu) in CuTi is also large which is up to 14.0 at.%. For other binary compounds CoTi2, CuTi2, Cu4Ti3 and Cu3Ti2, the ternary solubilities are remarkable too. No ternary compound has been detected. Nine three-phase equilibria were determined and three others in the Ti-enriched corner were estimated. Further investigations are essential to confirm the possible ternary phase reported and to determine the invariant reactions in the ternary system

  10. First-Principles Band Calculations on Electronic Structures of Ag-Doped Rutile and Anatase TiO2

    Institute of Scientific and Technical Information of China (English)

    HOU Xing-Gang; LIU An-Dong; HUANG Mei-Dong; LIAO Bin; WU Xiao-Ling

    2009-01-01

    The electronic structures of Ag-doped rutile and anatase TiO2 are studied by first-principles band calculations based on density funetionai theory with the full-potentiai linearized-augraented-plane-wave method.New occupied bands ore found between the band gaps of both Ag-doped rutile and anatase TiO2.The formation of these new bands Capri be explained mainly by their orbitals of Ag 4d states mixed with Ti 3d states and are supposed to contribute to their visible light absorption.

  11. Hybrid matrices of TiO2 and TiO2–Ag nanofibers with silicone for high water flux photocatalytic degradation of dairy effluent

    DEFF Research Database (Denmark)

    Kanjwal, Muzafar Ahmad; Alm, Martin; Thomsen, Peter;

    2016-01-01

    TiO2 and TiO2–Ag nanofibers were produced by electrospinning technique and surface coated on silicone elastomer (diameter: 10.0 mm; thickness: 2.0 mm) by dipcoating method. These coated hybrid nanoporous matrices were characterized by various morphological and physicochemical techniques (like SEM...... flux and water photosplitting properties......., TEM, XRD, FTIR, EDS and UV). These characterizations reveal that the surface morphology of electrospun nanofibers remain intact by the dipcoating technique. The produced hybrid matrices of TiO2 and TiO2–Ag silicone were utilized as photocatalysts to degrade dairy waste water with an efficient water...

  12. Thermal spikes in Ag/Fe and Cu/Fe ion beam mixing

    International Nuclear Information System (INIS)

    Ion beam mixing has been studied since 1980, and since then a lot of experimental and theoretical work has been done and knowledge has been gathered. Nevertheless, there are still many fundamental aspects that need to be clarified and with that aim many experiments need to be performed. Copper and iron are miscible in the liquid state, while silver and iron are not. However, both systems are thermally immiscible in the solid state. In order to have an insight into the importance of mixing within thermal spikes during ion beam irradiation, we deposited Cu/Fe and Ag/Fe bilayers onto Si substrates and irradiated them at room temperature with 2 MeV Cu and 2.5 MeV Au ions. A combination of Rutherford backscattering spectrometry (RBS) and atomic force microscopy (AFM) was used to analyze the atomic transport at the interface and the morphology changes of the samples. From the element profiles at the interface we conclude a mixing efficiency, which is indeed larger than the prediction of the ballistic model in the Cu/Fe system and smaller in the Ag/Fe system. Since ballistic mixing is expected in any case, we argue that demixing and phase separation in the Ag/Fe system occur in the thermal spike phase of the cascade as a consequence of the positive heat of mixing. Further mixing does occur in the thermal spike in the Cu/Fe system and they remain mixed even at the solid state because of the high cooling rate. In addition, ion irradiation induces a large surface roughening of the Ag and Cu top layers as proven by AFM. This effect is important for the correct interpretation of the results. Furthermore, this recrystallization affects also the interface, producing a rough interface, that appears in the RBS spectra as an atomic 'diffusion' at the interface

  13. Formation process of liquid in interface of Ti/Cu contact reaction couple

    Institute of Scientific and Technical Information of China (English)

    WU Ming-fang; YU Chun; YU Zhi-shi; LI Rui-feng

    2005-01-01

    By using the Ti/Cu contact reaction couples,the dissolution behavior of Ti and Cu in the eutectic reaction process was investigated under different conditions.The results show that the formation of eutectic liquid phase has a directional property,I.e.the eutectic liquid phase forms first at the Cu side and then spreads along the depth direction of Cu.The width of the eutectic liquid zone when Ti is placed on Cu is wider than that when Ti is placed under Cu.The shape of the upside liquid zone is wave-like.This phenomenon indicates that the formation process and spreading behavior in the upside are different from those in the underside,and there exists void effect in the Cu side of underside liquid zone,this will result in the delaying phenomenon of the contact reaction between Ti and Cu,and distinctly different shapes of the both liquid zones.The formation process of Ti/Cu eutectic liquid zone is similar to that of the traditional solid-state diffusion layer,and the relationship between the width of liquid zone and holding time obeys a square root law.

  14. Substrate dependent bonding distances of PTCDA - A comparative XSW study on Cu(111) and Ag(111)

    OpenAIRE

    Gerlach, A; Sellner, S.; Schreiber, F.; Koch, N; Zegenhagen, J.

    2006-01-01

    We study the adsorption geometry of 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) on Ag(111) and Cu(111) using X-ray standing waves. The element-specific analysis shows that the carbon core of the molecule adsorbs in a planar configuration, whereas the oxygen atoms experience a non-trivial and substrate dependent distortion. On copper (silver) the carbon rings resides 2.66 A (2.86 A) above the substrate. In contrast to the conformation on Ag(111), where the carboxylic oxygen atoms are...

  15. Non-UV germicidal activity of fresh TiO2 and Ag/TiO2

    Institute of Scientific and Technical Information of China (English)

    LIU Lifen; John Barford; YEUNG King Lun

    2009-01-01

    Fresh TiO2 was found to possess a strong germicidal activity even without UV irradiation. Live Yeast (Saccharomyces cerevisiae) cells in contact with fresh TiO2 were found deformed and dead after 15 min contact. The cause of germicidal activity was discussed from the observed cell deformation, lysis and increased absorption at 1680 cm-1 in FT-IR spectra of the affected cells, which proved the oxidizing effect of fresh TiO2 to cells. The deformation caused by the stretching of cell wall and pressure built-up inside the cell, led to cell burst and release of intracellular materials. The degree of cell deformation was found positively related with the wetting property of TiO2. Cells are negatively charged, for Gram-negative cell (thinner cell wall), a higher germicidal effect was observed than Gram-positive cells. The germicidal effect of TiO2 gradually decreases after exposure to air at room temperature, as the wetting property decreases. This kind of germicidal activity was more effective compared to other germicidal process such as UVA/TiO2 or Ag+. This shed light on designing new germicidal material either maintained by visible light irradiation, or by oxidation effect generated by reactive oxygen species.

  16. TiO2 nanocrystal incorporated with CuO and its optical properties

    International Nuclear Information System (INIS)

    TiO2 nanocrystal doped with Cu has been fabricated by wet chemical processing. The obtained results of x-ray diffraction, optical absorption in the UV–Vis bands and luminescence spectra have shown that Cu has substituted Ti in the structure of TiO2 anatase phase when the Cu concentration is about 8 at%. In the case of larger Cu concentrations the copper oxide appeared and increased with increasing Cu concentration. The samples doped with Cu strongly absorb the visible light (400–900 nm) and their absorption edge shifts to the longer wavelength in dependence on the Cu concentration. The absorption in the visible light band is attributed to transitions between the impurities levels of Cu created in the energy band gap of TiO2. In addition, an absorption shoulder above 800 nm is observed and supposed to be related with the absorption of CuO. The experimental results prove that the TiO2 anatase doped with Cu is suitable for hydrogen generation by photocatalytic water splitting under sunlight. (paper)

  17. Effect of Ti seed layers on structure of self-organized epitaxial face-centered-cubic-Ag(001) oriented nanodots

    Energy Technology Data Exchange (ETDEWEB)

    Kamiko, M.; Nose, K. [Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Suenaga, R.; Kyuno, K. [Department of Material Science, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); Koo, J.-W.; Ha, J.-G. [Department of Electronic Materials Engineering, Kwangwoon University, 447-1 Wolgye-Dong, Nowon-Gu, Seoul 139-701 (Korea, Republic of)

    2013-12-28

    The influence of Ti seed layers on the structure of self-organized Ag nanodots, obtained with a Ti seed-layer-assisted thermal agglomeration method, has been investigated. The samples were grown on MgO(001) single crystal substrates by RF magnetron sputter deposition. The samples were deposited at room temperature and post-annealed at 350 °C for 4 h while maintaining the chamber vacuum conditions. The results of atomic force microscopy (AFM) observations indicated that the insertion of the Ti seed layer (0.6–5.0 nm) between the MgO substrate and Ag layer promotes the agglomeration process, forming the nanodot array. Comparisons between the AFM images revealed that the size of the Ag nanodots was increased with an increase in the Ti seed layer thickness. The atomic concentration of the film surface was confirmed by X-ray photoelectron spectroscopy (XPS). The XPS result suggested that the nanodot surface mainly consisted of Ag. Moreover, X-ray diffraction results proved that the initial deposition of the Ti seed layer (0.6–5.0 nm) onto MgO(001) prior to the Ag deposition yielded high-quality fcc-Ag(001) oriented epitaxial nanodots. The optical absorbance spectra of the fabricated Ag nanodots with various Ti seed layer thicknesses were obtained in the visible light range.

  18. Preparation, characterization, and antibacterial activity of NiFe2O4/PAMA/Ag-TiO2 nanocomposite

    Science.gov (United States)

    Allafchian, Alireza; Jalali, Seyed Amir Hossein; Bahramian, Hamid; Ahmadvand, Hossein

    2016-04-01

    We have described a facile fabrication of silver deposited on the TiO2, Poly Acrylonitrile Co Maleic Anhydride (PAMA) polymer and nickel ferrite composite (NiFe2O4/PAMA/Ag-TiO2) through a three-step procedure. A pre-synthesized NiFe2O4 was first coated with PAMA polymer and then Ag-TiO2 was deposited on the surface of PAMA polymer shell. After the characterization of this three-component composite by various techniques, such as FTIR, XRD, FESEM, BET, TEM and VSM, it was impregnated in standard antibiotic discs. The antibacterial activity of NiFe2O4/PAMA/Ag-TiO2 nanocomposite was investigated against some gram positive and gram negative bacteria by employing disc diffusion assay and then compared with that of naked NiFe2O4, NiFe2O4/Ag, AgNPs and NiFe2O4/PAMA. The results demonstrated that the AgNPs, when embedded in TiO2 and combined with NiFe2O4/PAMA, became an excellent antibacterial agent. The NiFe2O4/PAMA/Ag-TiO2 nanocomposite could be readily separated from water solution after the disinfection process by applying an external magnetic field.

  19. Improved electrochemical performance of Ag-modified Li4Ti5O12 anode material in a broad voltage window

    Indian Academy of Sciences (India)

    Yan-Rong Zhu; Ting-Feng Yi; Hong-Tao Ma; Yong-Quan Ma; Li-Juan Jiang; Rong-Sun Zhu

    2014-01-01

    Li4Ti5O12/Ag composites were synthesized by a solid-state method. The effect of Ag modification on the physical and electrochemical properties is discussed by the characterizations of X-ray diffraction, scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy, cycling and rate tests. The lattice parameter of Li4Ti5O12 with a low Ag content is almost not changed, but the lattice parameter becomes larger due to the high content of Ag. Li4Ti5O12/Ag material has a uniform particle size which is about 1 m. Modification of appropriate Ag is beneficial to the reversible intercalation and deintercalation of Li+. Modification of Ag not only decreases the charge transfer resistance of Li4Ti5O12 material, but also improves the diffusion coefficient of lithium ion. Li4Ti5O12/Ag (3 mass%) material has the lowest charge transfer resistance, the highest diffusion coefficient of lithium ion and the best rate cycling performance.

  20. Impacts of Pristine and Transformed Ag and Cu Engineered Nanomaterials on Surficial Sediment Microbial Communities Appear Short-Lived.

    Science.gov (United States)

    Moore, Joe D; Stegemeier, John P; Bibby, Kyle; Marinakos, Stella M; Lowry, Gregory V; Gregory, Kelvin B

    2016-03-01

    Laboratory-based studies have shown that many soluble metal and metal oxide engineered nanomaterials (ENM) exert strong toxic effects on microorganisms. However, laboratory-based studies lack the complexity of natural systems and often use "as manufactured" ENMs rather than more environmentally relevant transformed ENMs, leaving open the question of whether natural ligands and seasonal variation will mitigate ENM impacts. Because ENMs will accumulate in subaquatic sediments, we examined the effects of pristine and transformed Ag and Cu ENMs on surficial sediment microbial communities in simulated freshwater wetlands. Five identical mesocosms were dosed through the water column with either Ag(0), Ag2S, CuO or CuS ENMs (nominal sizes of 4.67 ± 1.4, 18.1 ± 3.2, 31.1 ± 12, and 12.4 ± 4.1, respectively) or Cu(2+). Microbial communities were examined at 0, 7, 30, 90, 180, and 300 d using qPCR and high-throughput 16S rRNA gene sequencing. Results suggest differential short-term impacts of Ag(0) and Ag2S, similarities between CuO and CuS, and differences between Cu ENMs and Cu(2+). PICRUSt-predicted metagenomes displayed differential effects of Ag treatments on photosynthesis and of Cu treatments on methane metabolism. By 300 d, all metrics pointed to reconvergence of ENM-dosed mesocosm microbial community structure and composition, suggesting that the long-term microbial community impacts from a pulse of Ag or Cu ENMs are limited. PMID:26841726

  1. Defective TiO2-supported Cu nanoparticles as efficient and stable electrocatalysts for oxygen reduction in alkaline media

    Science.gov (United States)

    Liu, Ke; Song, Yang; Chen, Shaowei

    2014-12-01

    Nanocomposites based on TiO2-supported copper nanoparticles were prepared by a hydrothermal method where copper nanoparticles with or without the passivation of 1-decyne were chemically grown onto TiO2 nanocolloid surfaces (and hence denoted as CuHC10/TiO2 and Cu/TiO2, respectively). Transmission electron microscopy measurements showed that the size of the hybrid nanoparticles was 5-15 nm in diameter with clearly defined lattice fringes for anatase TiO2(101) and Cu(111). The formation of anatase TiO2 nanoparticles was also observed by X-ray diffraction measurements. FTIR measurements confirmed successful attachment of alkyne ligands onto the surface of the copper nanoparticles via Cu-C&z.tbd; interfacial bonds in CuHC10/TiO2. XPS measurements suggested the formation of CuO in both samples with a higher concentration in Cu/TiO2, and interestingly Ti3+ species were found in CuHC10/TiO2 but were absent in Cu/TiO2 or TiO2 nanoparticles. Electrochemical studies demonstrated that both Cu/TiO2 and CuHC10/TiO2 exhibited a markedly improved electrocatalytic performance in the oxygen reduction reaction, as compared to TiO2 nanocolloids alone, in the context of the onset potential, the number of electrons transferred and the kinetic current density. Importantly, among the series, CuHC10/TiO2 exhibited the best ORR activity with a high current density, an almost four-electron reduction pathway and long-term stability after 4000 cycles at high potentials, which may be ascribed to the defective TiO2 structures in combination with surface ligand engineering.Nanocomposites based on TiO2-supported copper nanoparticles were prepared by a hydrothermal method where copper nanoparticles with or without the passivation of 1-decyne were chemically grown onto TiO2 nanocolloid surfaces (and hence denoted as CuHC10/TiO2 and Cu/TiO2, respectively). Transmission electron microscopy measurements showed that the size of the hybrid nanoparticles was 5-15 nm in diameter with clearly defined

  2. Characteristic of TiNi(Cu) shape memory thin film based on micropump

    Science.gov (United States)

    Zhang, Huijun; Qiu, Chengjun

    2009-07-01

    Shape memory thin films offer a unique combination of novel properties and have the potential to become a primary actuating mechanism for micropumps. In this study, a micropump driven by TiNiCu shape memory thin film is designed and fabricated. The micropump is composed of a TiNiCu/Si bimorph driving membrane, a pump chamber and two inlet and outlet check valves. The property of TiNiCu films and driving capacity of TiNiCu/Si bimorph driving membrane are investigated. By using the recoverable force of TiNiCu thin film and biasing force of silicon membrane, the actuation diaphragm realizes reciprocating motion effectively. Experimental results show that the film surface appears a smooth and featureless morphology without any cracks, and the hysteresis width ΔT of TiNiCu film is about 2-3°C, the micropump driving by TiNiCu film has good performance, such as high pumping yield, high working frequency, stable driving capacity, and long fatigue life time.

  3. Influence of thermomechanical processing on the structure and properties of Cu-Ag alloy in situ composites

    Institute of Scientific and Technical Information of China (English)

    NING; Yuan-tao; ZHANG; Xiao-hui; ZHANG; Jie

    2005-01-01

    The influences of the thermomechanical processing, including the solidification conditions, the cold deformation and the intermediate annealing treatment, on the structure and properties of the Cu-10Ag alloy in situ composite were studied in this paper. The cast structure and the structural changes in the cold deformation and intermediate annealing process were observed. The properties including the ultimate tensile strength (UTS) and the electrical conductivity were determined. A two-stage strain strengthening effect for the Cu-10Ag alloy in situ filamentary composite was observed. The factors influencing the UTS and conductivity were discussed. The solidification conditions in the range of 10-1000 K/s cooling rates and the intermediate heat treatment showed obviously influence on the structure and properties on the Cu-10Ag alloy in situ filamentary composite. The typical properties of the Cu-Ag alloy in situ filamentary composites through thermomechanical processing were reported.

  4. Efficient enhancement of hydrogen production by Ag/Cu2O/ZnO tandem triple-junction photoelectrochemical cell

    International Nuclear Information System (INIS)

    Highly efficient semiconductor photoelectrodes for solar hydrogen production through photocatalytic water splitting are a promising and challenge solution to solve the energy problems. In this work, Ag/Cu2O/ZnO tandem triple-junction photoelectrode was designed and prepared. An increase of 11 times of photocurrent is achieved in the Ag/Cu2O/ZnO photoelectrode comparing to that of the Cu2O film. The high performance of the Ag/Cu2O/ZnO film is due to the optimized design of the tandem triple-junction structure, where the localized surface Plasmon resonance of Ag and the hetero-junctions efficiently absorb solar energy, produce, and separate electron-hole pairs in the photocathode

  5. Intermetallic compound formation in Sn-Co-Cu, Sn-Ag-Cu and eutectic Sn-Cu solder joints on electroless Ni(P) immersion Au surface finish after reflow soldering

    International Nuclear Information System (INIS)

    The interfacial reactions between Sn-0.4Co-0.7Cu eutectic alloy and immersion Au/electroless Ni(P)/Cu substrate were investigated after reflow soldering at 260 deg. C for 2 min. Common Sn-4.0Ag-0.5Cu and eutectic Sn-0.7Cu solders were used as reference. Two types of intermetallic compounds (IMC) were found in the solder matrix of the Sn-0.4Co-0.7Cu alloy, namely coarser CoSn2 and finer Cu6Sn5 particles, while only one ternary (Cu, Ni)6Sn5 interfacial compound was detected between the solder alloy and the electroless nickel and immersion gold (ENIG) coated substrate. The same trend was also observed for the Sn-Ag-Cu and Sn-Cu solder joints. Compared with the CoSn2 particles found in the Sn-Co-Cu solder and the Ag3Sn particles found in the Sn-Ag-Cu solder, the Cu6Sn5 particles found in both solder systems exhibited finer structure and more uniform distribution. It was noted that the thickness of the interfacial IMCs for the Sn-Co-Cu, Sn-Ag-Cu and Sn-Cu alloys was 3.5 μm, 4.3 μm and 4.1 μm, respectively, as a result of longer reflow time above the alloy's melting temperature since the Sn-Ag-Cu solder alloy has the lowest melting point

  6. Intermetallic compound formation in Sn-Co-Cu, Sn-Ag-Cu and eutectic Sn-Cu solder joints on electroless Ni(P) immersion Au surface finish after reflow soldering

    Energy Technology Data Exchange (ETDEWEB)

    Sun Peng [Key State Lab for New Displays and System Integration (Chinese Ministry of Education), SMIT Center, Shanghai University, 200072 Shanghai (China) and Department of Microtechnology and Nanoscience, SMIT Center, Chalmers University of Technology, 412-96 Goeteborg (Sweden)]. E-mail: peng.sun@mc2.chalmers.se; Andersson, Cristina [Department of Microtechnology and Nanoscience, SMIT Center, Chalmers University of Technology, 412-96 Goeteborg (Sweden); Wei Xicheng [Key State Lab for New Displays and System Integration (Chinese Ministry of Education), SMIT Center, Shanghai University, 200072 Shanghai (China); Cheng Zhaonian [Department of Microtechnology and Nanoscience, SMIT Center, Chalmers University of Technology, 412-96 Goeteborg (Sweden); Shangguan Dongkai [Flextronics International, San Jose, CA (United States); Liu Johan [Key State Lab for New Displays and System Integration (Chinese Ministry of Education), SMIT Center, Shanghai University, 200072 Shanghai (China); Department of Microtechnology and Nanoscience, SMIT Center, Chalmers University of Technology, 412-96 Goeteborg (Sweden)

    2006-11-25

    The interfacial reactions between Sn-0.4Co-0.7Cu eutectic alloy and immersion Au/electroless Ni(P)/Cu substrate were investigated after reflow soldering at 260 deg. C for 2 min. Common Sn-4.0Ag-0.5Cu and eutectic Sn-0.7Cu solders were used as reference. Two types of intermetallic compounds (IMC) were found in the solder matrix of the Sn-0.4Co-0.7Cu alloy, namely coarser CoSn{sub 2} and finer Cu{sub 6}Sn{sub 5} particles, while only one ternary (Cu, Ni){sub 6}Sn{sub 5} interfacial compound was detected between the solder alloy and the electroless nickel and immersion gold (ENIG) coated substrate. The same trend was also observed for the Sn-Ag-Cu and Sn-Cu solder joints. Compared with the CoSn{sub 2} particles found in the Sn-Co-Cu solder and the Ag{sub 3}Sn particles found in the Sn-Ag-Cu solder, the Cu{sub 6}Sn{sub 5} particles found in both solder systems exhibited finer structure and more uniform distribution. It was noted that the thickness of the interfacial IMCs for the Sn-Co-Cu, Sn-Ag-Cu and Sn-Cu alloys was 3.5 {mu}m, 4.3 {mu}m and 4.1 {mu}m, respectively, as a result of longer reflow time above the alloy's melting temperature since the Sn-Ag-Cu solder alloy has the lowest melting point.

  7. Plasmon-enhanced photocatalytic hydrogen production over visible-light responsive Cu/TiO2

    International Nuclear Information System (INIS)

    Cheap and visible-light responsive Cu/TiO2 photocatalysts were fabricated by illuminating ultraviolet (UV) to a mixture of TiO2 nanoparticles (NPs) and Cu2O NPs in an evacuated reaction chamber. The Cu2O NPs were reduced by UV in an oxygen-free reaction chamber, and hence, metallic Cu NPs with size less than 5 nm were uniformly loaded on TiO2. Due to the plasmon resonance of the Cu NPs, the Cu/TiO2 exhibited a good performance of water-splitting hydrogen production under visible light in the presence of glycerol as a hole scavenger. The optimum hydrogen production rate of Cu/TiO2 was 0.24 mmol h−1 g−1. The Cu/TiO2 also showed high stability of the photocatalytic performance in the evacuated chamber; however, the visible-light responsive photocatalytic properties dramatically and rapidly decreased when exposed to air. (paper)

  8. First-principles study of Cu/TiN and Al/TiN interfaces: weak versus strong interfaces

    International Nuclear Information System (INIS)

    Using density functional theory based first-principles calculations, we show that the preferred interfacial plane orientation relationship is determined by the strength of bonding at the interface. The thermodynamic stability, and the ideal tensile and shear strengths of Cu(1 1 1)/TiN(1 1 1) and Al(1 1 1)/TiN(1 1 1) interfaces are calculated. While there is a strong orientation relation preference for the Al/TiN interface, there is no orientation relation preference for the Cu/TiN interface. Both the ideal tensile and shear strengths of Cu/TiN interfaces are lower than those of bulk Cu and TiN, suggesting such interfaces are weaker than their bulk components. By comparison, the ideal strengths of the Al/TiN interface are comparable to the constituents in the bulk form. Such contrasting interfaces can be a test-bed for studying the role of interfaces in determining the mechanical behavior of the nanolayered structures. (paper)

  9. p-Cu2O-shell/n-TiO2-nanowire-core heterostucture photodiodes

    OpenAIRE

    Tsai, Tsung-Ying; Chang, Shoou-Jinn; Hsueh, Ting-Jen; Hsueh, Han-Ting; Weng, Wen-Yin; Hsu, Cheng-Liang; Dai, Bau-Tong

    2011-01-01

    This study reports the deposition of cuprous oxide [Cu2O] onto titanium dioxide [TiO2] nanowires [NWs] prepared on TiO2/glass templates. The average length and average diameter of these thermally oxidized and evaporated TiO2 NWs are 0.1 to 0.4 μm and 30 to 100 nm, respectively. The deposited Cu2O fills gaps between the TiO2 NWs with good step coverage to form nanoshells surrounding the TiO2 cores. The p-Cu2O/n-TiO2 NW heterostructure exhibits a rectifying behavior with a sharp turn-on at appr...

  10. Experimental study of the ternary Ag-Cu-In phase diagram

    International Nuclear Information System (INIS)

    The phase diagram of the Ag-Cu-In system was investigated using powder X-ray diffraction (XRD), differential scanning calorimetry (DSC) and electron probe microanalysis (EPMA). Two isothermal sections (at 510 and 607 deg. C) and 15 isopletic sections were studied. The results showed seven ternary peritectics, one ternary eutectic and one ternary metatectic. A complete reaction scheme was constructed, the valleys were drawn and the liquidus surfaces were derived from DSC data in the entire composition range.

  11. Experimental study of the ternary Ag-Cu-In phase diagram

    Energy Technology Data Exchange (ETDEWEB)

    Bahari, Zahra [Laboratoire de chimie physique et minerale, Faculte des sciences pharmaceutiques et biologiques, Universite Paris Descartes, avenue de l' Observatoire, 75006 Paris (France); Laboratoire de chimie du solide mineral (LCSM), Faculte des sciences, Universite Mohamed 1er, Route Sidi Maafa, B.P. 524, Oujda, Maroc (Morocco); Elgadi, Mohamed [Laboratoire de chimie du solide mineral (LCSM), Faculte des sciences, Universite Mohamed 1er, Route Sidi Maafa, B.P. 524, Oujda, Maroc (Morocco); Rivet, Jacques [Laboratoire de chimie physique et minerale, Faculte des sciences pharmaceutiques et biologiques, Universite Paris Descartes, avenue de l' Observatoire, 75006 Paris (France); Dugue, Jerome [Laboratoire de chimie physique et minerale, Faculte des sciences pharmaceutiques et biologiques, Universite Paris Descartes, avenue de l' Observatoire, 75006 Paris (France)], E-mail: jerome.dugue@univ-paris5.fr

    2009-05-27

    The phase diagram of the Ag-Cu-In system was investigated using powder X-ray diffraction (XRD), differential scanning calorimetry (DSC) and electron probe microanalysis (EPMA). Two isothermal sections (at 510 and 607 deg. C) and 15 isopletic sections were studied. The results showed seven ternary peritectics, one ternary eutectic and one ternary metatectic. A complete reaction scheme was constructed, the valleys were drawn and the liquidus surfaces were derived from DSC data in the entire composition range.

  12. Calculating model of mass action concentrations for Ag-Au-Cu melts

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on phase diagrams and measured activities, the calculating model of mass action concentrations for heterogeneous melts Ag-Au-Cu was formulated. Calculated results agree with the improved results of recent research work.showing that the model formulated can reflect the structural characteristics of these melts. In this model, without the help of any empirical parameters, only three equilibrium constants are used, hence it is simple, lear, and favorable to the simplification of calculation.

  13. Dielectric performance of polymer-based composites containing core-shell Ag@TiO2 nanoparticle fillers

    Science.gov (United States)

    Liang, Fei; Zhang, Lu; Lu, Wen-Zhong; Wan, Qian-Xing; Fan, Gui-Fen

    2016-02-01

    This paper reports composites prepared by embedding core-shell Ag@TiO2 fillers into polytetrafluoroethylene. Ag nanoparticles were homogeneously coated with TiO2, to give a shell thickness of approximately ˜8-10 nm. The composite containing Ag@TiO2 nanoparticles with rutile shells exhibited better dielectric properties than the composite containing Ag@TiO2 nanoparticles with anatase shells. The relative permittivity (ɛr) of the composite containing 70 vol. % filler was approximately 240 at 100 Hz, which was more than 100 times higher than that of pure polytetrafluoroethylene (ɛr = 2.1). An effective medium percolation theory model is used to account for the dielectric constant of the composite.

  14. Cu-Au-Ag alloy nanoparticles incorporated silica films using a new three-layer deposition technique.

    Science.gov (United States)

    Pal, Sudipto; Bysakh, Sandip; De, Goutam

    2010-02-01

    Formation of Au-Ag-Cu ternary alloy nanoparticles (NPs) is difficult mainly because the system Cu/Ag is immiscible. We present a new synthetic technique to generate such ternary alloy NPs in silica film matrix employing a three-layer (3L) coating design. In this methodology three successive coating layers were deposited on silica glass substrates from separately prepared Cu-, Au- and Ag-ion incorporated inorganic-organic hybrid silica sols by dipping method. The Au layer is kept in the middle because it is miscible with both the Ag and Cu. The 3L film assembly was subjected to UV- and heat-treatment at 450-750 degrees C in H2-N2 atmosphere. UV-treatment generates small Au and Ag NPs in the respective layers and Cu remains as Cu2+; subsequent heat-treatment in H2-N2 induces the formation of ternary alloy NPs by the interlayer diffusion of nanometals. The final heat-treated film (750 degrees C/H2-N2) shows single and sharp plasmon band centered at 480 nm in the UV-visible spectrum indicating the formation of alloy (solid solution) NPs. GIXRD study shows one set of diffraction peaks which are shifted towards higher angle with respect to the Au or Ag diffraction peaks. FESEM, GIXRD, HRTEM, and SAED analyses reveal that the alloy has a composition close to (Au + Ag)0.88Cu0.12. The EDS analyses using the nano probe attached with TEM confirm the presence of Au, Ag and Cu in all the alloy NPs. PMID:20352717

  15. Effect of Core-Shell Ag@TiO2 Volume Ratio on Characteristics of TiO2-Based DSSCs

    Directory of Open Access Journals (Sweden)

    Ho Chang

    2014-01-01

    Full Text Available This paper aims to develop photoanode material required by dye-sensitized solar cells. The material prepared is in the form of Ag@TiO2 core-shell-type nanocomposites. This material is used to replace the titanium oxide powder commonly used in general DSSCs. The prepared Ag@TiO2 core-shell-type nanocomposites are mixed with Degussa P25 TiO2 in different proportions. Triton X-100 is added and polyethylene glycol (PEG at 20 wt% is used as a polymer additive. This study tests the particle size and material properties of Ag@TiO2 core-shell-type nanocomposites and measures the photoelectric conversion efficiency and IPCE of DSSCs. Experimental results show that the DSSC prepared by Ag@TiO2 core-shell-type nanocomposites can achieve a photoelectric conversion efficiency of 3.67%. When Ag@TiO2 core-shell-type nanocomposites are mixed with P25 nanoparticles in specific proportions, and when the thickness of the photoelectrode thin film is 28 μm, the photoelectric conversion efficiency can reach 6.06%, with a fill factor of 0.52, open-circuit voltage of 0.64V, and short-circuit density of 18.22 mAcm−2. Compared to the DSSC prepared by P25 TiO2 only, the photoelectric conversion efficiency can be raised by 38% under the proposed approach.

  16. Numerical Simulation of Brazing TiC Cermet to Iron with TiZrNiCu Filler Metal

    Institute of Scientific and Technical Information of China (English)

    Lixia ZHANG; Jicai FENG

    2004-01-01

    The maximum thermal stress and stress concentration zones of iron/TiC cermet joint during cooling were studied in this paper. The results showed that the shear stress on iron/TiC cermet joint concentrates on the interface tip and the maximum shear stress appears on the left tip of iron/TiZrNiCu interlace. Positive tensile stress on TiC cermet undersurface concentrates on both sides of TiC cermet and its value decreases during cooling. Negative tensile stress on TiC cermet undersurface concentrates on the center of TiC cermet and its value increases during cooling. Brazing temperature has little effect on the development and maximum thermal stress.

  17. Localized TiSi and TiN phases in Si/Ti/Al/Cu Ohmic contacts to AlGaN/GaN heterostructures

    International Nuclear Information System (INIS)

    Microstructural changes in Si/Ti/Al/Cu (10/40/60/50 nm) Ohmic contacts to AlGaN/GaN heterostructure were investigated for complementary metal-oxide semiconductor compatible processes. Si/Ti/Al/Cu metallization exhibited a low specific contact resistance of 3.6 × 10−6 Ω-cm2 and contact resistance of 0.46 Ω-mm when a Si interfacial layer was used. Without a designated barrier metal, TiSix alloys that formed in the metallic region effectively suppressed Cu diffusion. The shallow TiN junction in AlGaN/GaN was attributed to TiSix in the metallic regions. Microstructural changes were detected by systematic physical characterization. (paper)

  18. Localized TiSi and TiN phases in Si/Ti/Al/Cu Ohmic contacts to AlGaN/GaN heterostructures

    Science.gov (United States)

    Yoon, Seonno; Song, Yunwon; Lee, Seung Min; Lee, Hi-Deok; Oh, Jungwoo

    2016-05-01

    Microstructural changes in Si/Ti/Al/Cu (10/40/60/50 nm) Ohmic contacts to AlGaN/GaN heterostructure were investigated for complementary metal-oxide semiconductor compatible processes. Si/Ti/Al/Cu metallization exhibited a low specific contact resistance of 3.6 × 10-6 Ω-cm2 and contact resistance of 0.46 Ω-mm when a Si interfacial layer was used. Without a designated barrier metal, TiSix alloys that formed in the metallic region effectively suppressed Cu diffusion. The shallow TiN junction in AlGaN/GaN was attributed to TiSix in the metallic regions. Microstructural changes were detected by systematic physical characterization.

  19. Hot Electron Attenuation Length Measurements of Cu and Ag using BEEM

    Science.gov (United States)

    Garramone, John; Abel, Joseph; Sitnitsky, Ilona; Zhao, Lai; Appelbaum, Ian; Labella, Vincent

    2010-03-01

    33.4˜2.9 nm 1.0 eV Understanding electron transport and scattering in nanoscale Cu and Ag structures is important for modern integrated circuit technology and futuristic applications such as spintronics and hydrogen sensing footnotetextHuang et al., Rev. Lett. 99 177209 (2007)^,footnotetextNienhaus et at., Appl. Phys. Lett. 74 4046 (1999). In this study we will report on hot electron attenuation length measurements of nanometer thick films of Cu and Ag on the Si substrate utilizing ballistic electron emission microscopy (BEEM). BEEM is a three terminal scanning tunneling microcopy (STM) based technique where electrons are injected from a STM tip into a grounded metal base of a Schottky diode. The electrons that transverse the metal overlayer and surmount the Schottky barrier are measured as the BEEM current by a backside contact to the semiconductor. The attenuation length is extracted by measuring the falloff in BEEM current as a function of metal film thickness. The hot electron attenuation length for Cu of is measured at a tip bias of and a temperature of 80 K. Results for Ag will also be presented as well as models used to extract the relative contribution of elastic and inelastic electron scattering in the metal films as a function of electron energy.

  20. Ag2CuMnO4: A new silver copper oxide with delafossite structure

    International Nuclear Information System (INIS)

    The use of hydrothermal methods has allowed the synthesis of a new silver copper mixed oxide, Ag2CuMnO4, the first example of a quaternary oxide containing both elements. It crystallizes with the delafossite 3R structure, thus being the first delafossite to contain both Ag and Cu. Synthesis conditions affect the final particle size (30-500nm). Powder X-ray diffraction Rietveld refinement indicates a trigonal structure (R3-bar m) and cell parameters a=2.99991A and c=18.428A, where Cu and Mn are disordered within the octahedral B positions in the plane and linearly coordinated Ag occupies de A position between layers. X-ray absorption near edge spectroscopy (XANES) for copper and manganese, and XPS for silver evidence +2, +4, and +1 oxidation states. The microstructure consists of layered particles that may form large twins showing 5nm nanodomains. Finally, magnetic measurements reveal the existence of ferromagnetic coupling yielding in-plane moments that align antiferromagnetically at lower temperatures. The singularity of the new phase resides on the fact that is an example of a bidimensional arrangement of silver and copper in an oxide that also shows clear bidimensionality in its physical properties. That is of special relevance to the field of high Tc superconducting oxides, while the ferromagnetic coupling in a bidimensional system deserves itself special attention

  1. Surface dynamics of Cu and Ag atoms on hydroxylated MgO(001) surfaces

    International Nuclear Information System (INIS)

    Density-functional theory calculations were performed to investigate the surface dynamics of Cu and Ag (XM) atoms on MgO(001) surfaces with surface-functional hydroxyl groups. The adsorption, diffusion, bonding, and electronic structure of XM on these surfaces are presented. The results indicate a large energy gain in the adsorption of XM on MgOhdr(001) with respect to XM on MgO(001). This suggests that the adsorption of XM is stronger on MgOhdr(001). Further analysis shows that in the presence of surface hydroxyl groups, XM atoms preferentially form XMOH complexes instead of XM dimers. The surface diffusion barriers of XMOH on MgO(001) [XM on MgOhdr(001)] are calculated. CuOH is found to have a higher surface diffusion energy barrier than AgOH, but a slightly lower energy barrier to diffusion than AuOH. Therefore, sintering of Ag on MgOhdr(001) surfaces is expected to be different from that of Cu or Au. Finally, the electronic structures and charge rearrangements of XM on MgOhdr(001) are presented and compared with those of Au on MgOhdr(001).

  2. High coercivity and giant magnetoresistance of CoAg, CoCu granular films

    International Nuclear Information System (INIS)

    We report our study on the structure, magnetic and giant magnetoresistance properties of two systems: Co x Ag1-x (x=33, 48, 49, 52 at%) and Co y Cu1-y (y=11, 13, 15, 17 at%) granular films prepared by RF sputtering. The thermal transition measured by the SDT 2960 apparatus revealed exothermal peaks at 400 deg. C, corresponding to the crystallization of FCC-Co crystallites. The studied films were annealed in a temperature range of 300-450 deg. C for 1 h. The structure and particle size were determined from the X-ray diffraction data. Superparamagnetic state was shown in as-deposited films. After appropriate heat treatment, coercivity increased up to 1100 Oe in the Co52Ag48 film annealed at 350 deg. C, and 690 Oe in the Co13Cu87 film annealed at 400 deg. C. Maximum magnetoresistance up to 4.25% in the Co48Ag52 film, and 5.4% in the Co15Cu85 film annealed at 400 deg. C was obtained. Our values for magnetoresistance are quite high compared with recent studies

  3. Combinatorial development of antibacterial Zr-Cu-Al-Ag thin film metallic glasses

    Science.gov (United States)

    Liu, Yanhui; Padmanabhan, Jagannath; Cheung, Bettina; Liu, Jingbei; Chen, Zheng; Scanley, B. Ellen; Wesolowski, Donna; Pressley, Mariyah; Broadbridge, Christine C.; Altman, Sidney; Schwarz, Udo D.; Kyriakides, Themis R.; Schroers, Jan

    2016-05-01

    Metallic alloys are normally composed of multiple constituent elements in order to achieve integration of a plurality of properties required in technological applications. However, conventional alloy development paradigm, by sequential trial-and-error approach, requires completely unrelated strategies to optimize compositions out of a vast phase space, making alloy development time consuming and labor intensive. Here, we challenge the conventional paradigm by proposing a combinatorial strategy that enables parallel screening of a multitude of alloys. Utilizing a typical metallic glass forming alloy system Zr-Cu-Al-Ag as an example, we demonstrate how glass formation and antibacterial activity, two unrelated properties, can be simultaneously characterized and the optimal composition can be efficiently identified. We found that in the Zr-Cu-Al-Ag alloy system fully glassy phase can be obtained in a wide compositional range by co-sputtering, and antibacterial activity is strongly dependent on alloy compositions. Our results indicate that antibacterial activity is sensitive to Cu and Ag while essentially remains unchanged within a wide range of Zr and Al. The proposed strategy not only facilitates development of high-performing alloys, but also provides a tool to unveil the composition dependence of properties in a highly parallel fashion, which helps the development of new materials by design.

  4. Combinatorial development of antibacterial Zr-Cu-Al-Ag thin film metallic glasses.

    Science.gov (United States)

    Liu, Yanhui; Padmanabhan, Jagannath; Cheung, Bettina; Liu, Jingbei; Chen, Zheng; Scanley, B Ellen; Wesolowski, Donna; Pressley, Mariyah; Broadbridge, Christine C; Altman, Sidney; Schwarz, Udo D; Kyriakides, Themis R; Schroers, Jan

    2016-01-01

    Metallic alloys are normally composed of multiple constituent elements in order to achieve integration of a plurality of properties required in technological applications. However, conventional alloy development paradigm, by sequential trial-and-error approach, requires completely unrelated strategies to optimize compositions out of a vast phase space, making alloy development time consuming and labor intensive. Here, we challenge the conventional paradigm by proposing a combinatorial strategy that enables parallel screening of a multitude of alloys. Utilizing a typical metallic glass forming alloy system Zr-Cu-Al-Ag as an example, we demonstrate how glass formation and antibacterial activity, two unrelated properties, can be simultaneously characterized and the optimal composition can be efficiently identified. We found that in the Zr-Cu-Al-Ag alloy system fully glassy phase can be obtained in a wide compositional range by co-sputtering, and antibacterial activity is strongly dependent on alloy compositions. Our results indicate that antibacterial activity is sensitive to Cu and Ag while essentially remains unchanged within a wide range of Zr and Al. The proposed strategy not only facilitates development of high-performing alloys, but also provides a tool to unveil the composition dependence of properties in a highly parallel fashion, which helps the development of new materials by design. PMID:27230692

  5. Surface and transport properties of Cu-Sn-Ti liquid alloys

    Institute of Scientific and Technical Information of China (English)

    R. Novakovic; E. Ricci; S. Amore; T. Lanata

    2006-01-01

    The lack of experimental data and / or limited experimental information concerning both surface and transport properties of liquid alloys often require the prediction of these quantities. An attempt has been made to link the thermophysical properties of a ternary Cu-Sn-Ti system and its binary Cu-Sn, Cu-Ti and Sn-Ti subsystems with the bulk through the study of the concentration dependence of various thermodynamic, structural, surface and dynamic properties in the frame of the statistical mechanical theory in conjunction with the quasi-lattce theory (QLT). This formalism provides valuable qualitative insight into mixing processes that occur in molten alloys.

  6. Tailoring properties and functionalities of TiO2 and Ag nanoparticles involved in surfaces engineering processes

    OpenAIRE

    Ortelli, Simona

    2015-01-01

    The functionalization of substrates through the application of nanostructured coatings allows to create new materials, with enhanced properties. In this work, the development of self-cleaning and antibacterial textiles, through the application of TiO2 and Ag based nanostructured coatings was carried out. The production of TiO2 and Ag functionalized materials was achieved both by the classical dip-padding-curing method and by the innovative electrospinning process to obtain nanofibers doped wi...

  7. Catalytic decomposition of gaseous 1,2-dichlorobenzene over CuOx/TiO₂ and CuOx/TiO₂-CNTs catalysts: Mechanism and PCDD/Fs formation.

    Science.gov (United States)

    Wang, Qiu-lin; Huang, Qun-xing; Wu, Hui-fan; Lu, Sheng-yong; Wu, Hai-long; Li, Xiao-dong; Yan, Jian-hua

    2016-02-01

    Gaseous 1,2-dichlorobenzene (1,2-DCBz) was catalytically decomposed in a fixed-bed catalytic reactor using composite copper-based titanium oxide (CuOx/TiO2) catalysts with different copper ratios. Carbon nanotubes (CNTs) were introduced to produce novel CuOx/TiO2-CNTs catalysts by the sol-gel method. The catalytic performances of CuOx/TiO2 and CuOx/TiO2-CNTs on 1,2-DCBz oxidative destruction under different temperatures (150-350 °C) were experimentally examined and the correlation between catalyst structure and catalytic activity was characterized and the role of oxygen in catalytic reaction was discussed. Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) generation during 1,2-DCBz catalytic oxidation by CuOx/TiO2-CNTs composite catalyst was also examined. Results indicate that the 1,2-DCBz destruction/removal efficiencies of CuOx (4 wt%)/TiO2 catalyst at 150 °C and 350 °C with a GHSV of 3400 h(-1) are 59% and 94% respectively and low-temperature (150 °C) catalytic activity of CuOx/TiO2 on 1,2-DCBz oxidation can be improved from 59 to 77% when CNTs are introduced. Furthermore, oxygen either in catalyst or from reaction atmosphere is indispensible in reaction. The former is offered to activate and oxidize the 1,2-DCBz adsorbed on catalyst, thus can be generally consumed during reaction and the oxygen content in catalyst is observed lost from 39.9 to 35.0 wt% after reacting under inert atmosphere; the latter may replenish the vacancy in catalyst created by the consumed oxygen thus extends the catalyst life and raises the destruction/removal efficiency. The introduction of CNTs also increases the Cu(2+)/Cu(+) ratio, chemisorbed oxygen concentration and surface lattice oxygen binding energy which are closely related with catalytic activity. PCDD/Fs is confirmed to be formed when 1,2-DCBz catalytically oxidized by CuOx/TiO2-CNTs composite catalyst with sufficient oxygen (21%), proper temperature (350 °C) and high concentration of 1,2-DCBz feed (120 ppm

  8. PHOTOCALYTIC EFFICIENCY OF TiO Ag/TiO MULTILAYER 2 2 FILMS GROWN BY SOL-GEL TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Villa, K.

    2010-01-01

    Full Text Available Heterogeneous photocatalysis is a new oxidation advanced technology (OAT; it has become an alternative method for air and water purification as a very efficient for removing organic pollutants in the environment, such as pesticides, colors, and microorganisms, and they are completely mineralized by this process. One of the most common photocatalyst is titanium dioxide (TiO for being cheap, reusable, nontoxic, resistant to photocorrosion, 2 and with high oxidant power. However for this material, the efficient use of sunlight in photocatalysis needs a lower energy threshold for the photoexcitation. One way is by doping the TiO with transition metals and non- 2 metallic impurities. In this work, the growth of multilayer films TiO Ag/TiO through the sol-gel technique is 2 2 reported. As substrates were used conventional microscope slides, which were impregnated sequentially by immersion-extraction, with a solution containing the precursor of TiO and with one containing the precursor 2 adding AgNO to a constant concentration of 15%. The number of impregnated layers was varied and the sintering 3 temperature used was 600 °C. These films were characterized by x-ray diffraction and UV-Vis spectroscopy. The photocatalytical efficiency of the films was measured by the decolorization of a solution of methylene blue and those that showed better results were used to test on contaminated water samples, evaluating its power in the disinfection of total and fecal coliforms, and the organic load decrement (OLD after the photocatalytic process.

  9. Microstructural Observations in a Cast Al-Si-Cu/TiC Composite

    Science.gov (United States)

    Karantzalis, A. E.; Lekatou, A.; Georgatis, E.; Poulas, V.; Mavros, H.

    2010-06-01

    A 3-5 vol.% TiC particulate Al-Si-Cu composite was prepared by diluting Al/20 vol.% TiC composite in an Al-7Si-4Cu alloy matrix. TiC particle distribution consists of isolated and clustered particles which are both located at the primary-α grain boundaries and at the areas of the last solidified liquid. Particle pushing by the solidification front is responsible for the final particle location. The solidified microstructure consists of primary and intermetallic phases formed by a sequence of possible eutectic reactions. No evidence of TiC particle degradation was observed.

  10. Ag-loaded TiO2/reduced graphene oxide nanocomposites for enhanced visible-light photocatalytic activity

    Science.gov (United States)

    Vasilaki, E.; Georgaki, I.; Vernardou, D.; Vamvakaki, M.; Katsarakis, N.

    2015-10-01

    In this work, Ag nanoparticles were loaded by chemical reduction onto TiO2 P25 under different loadings ranging from 1 up to 4 wt% and hydrothermally deposited on reduced graphene oxide sheets. Chemical reduction was determined to be an effective preparation approach for Ag attachment to titania, leading to the formation of small silver nanoparticles with an average diameter of 4.2 nm. The photocatalytic performance of the hybrid nanocomposite materials was evaluated via methylene blue (MB) dye removal under visible-light irradiation. The rate of dye decolorization was found to depend on the metal loading, showing an increase till a threshold value of 3 wt%, above which the rate drops. Next, the as prepared sample of TiO2/Ag of better photocatalytic response, i.e., at a 3 wt% loading value, was hydrothermally deposited on a platform of reduced graphene oxide (rGO) of tunable content (mass ratio). TiO2/Ag/rGO coupled nanocomposite presented significantly enhanced photocatalytic activity compared to the TiO2/Ag, TiO2/rGO composites and bare P25 titania semiconductor photocatalysts. In particular, after 45 min of irradiation almost complete decolorization of the dye was observed for the TiO2/Ag/rGO nanocatalyst, while the respective removal efficiency was 92% for TiO2/Ag, 93% for TiO2/rGO and only 80% for the bare TiO2 nanoparticles. This simple step by step preparation strategy allows for optimum exploitation of the advanced properties of metal plasmonic effect and reduced graphene oxide as the critical host for boosting the overall photocatalytic activity towards visible-light.

  11. Photocatalytic Decomposition of N2O on Ag-TiO2

    Czech Academy of Sciences Publication Activity Database

    Kočí, K.; Krejčíková, Simona; Šolcová, Olga; Obalová, L.

    2012-01-01

    Roč. 191, č. 1 (2012), s. 134-137. ISSN 0920-5861. [International Symposium on Nitrogen Oxides Emission Abatement. Zakopane, 04.09.2011-07.09.2011] R&D Projects: GA ČR GA104/09/0694 Institutional support: RVO:67985858 Keywords : photocatalytic decomposition * N2O * Ag doping * TiO2 Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.980, year: 2012

  12. Effect of mesh patterning with UV pulsed-laser on optical and electrical properties of ZnO/Ag-Ti thin films

    International Nuclear Information System (INIS)

    In this study, the ZnO/Ag-Ti structure for transparence conducting oxide (TCO) is investigated by optimizing the thickness of the Ag-Ti alloy and ZnO layers. The Ag-Ti thin film is deposited by DC magnetron sputtering and its thicknesses is well controlled. The ZnO thin film is prepared by sol-gel method using zinc acetate as cation source, 2-methoxiethanol as solvent and monoethanolamine as solution stabilizer. The ZnO film deposition is performed by spin-coating technique and dried at 150 deg. C on Corning 1737 glass. Due to the conductivity of ZnO/Ag-Ti is dominated by Ag-Ti, the sheet resistance of ZnO/Ag-Ti decrease dramatically as the thickness of Ag-Ti layer increases. However, the transmittances of ZnO/Ag-Ti become unacceptable for TCO application after the thickness of Ag-Ti layer beyond 6 nm. The as-deposited ZnO/Ag-Ti structure has the optical transmittance of 83% - 500 nm and the low resistivity of 1.2 x 10-5 Ω-cm. Furthermore, for improving the optical and electrical properties of ZnO/Ag-Ti, the thermal treatment using laser is adopted. Experimental results indicate that the transmittance of ZnO/Ag-Ti is improved from 83% to 89% - 500 nm with resistivity of 1.02 x 10-5 Ω-cm after laser drilling. The optical spectrum, the resistance, and the morphology of the ZnO/Ag-Ti will be reported in the study.

  13. Photocatalytic performances and activities of Ag-doped CuFe{sub 2}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Zhengru, E-mail: zhengruzhu@gmail.com [Research Center of Hydrology and Water Source, School of Urban and Environment, Liaoning Normal University, Dalian, 116029 (China); State Key Laboratory of Fine Chemical, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024 (China); Li, Xinyong; Zhao, Qidong [State Key Laboratory of Fine Chemical, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024 (China); Li, Yonghua; Sun, Caizhi; Cao, Yongqiang [Research Center of Hydrology and Water Source, School of Urban and Environment, Liaoning Normal University, Dalian, 116029 (China)

    2013-08-01

    Graphical abstract: - Highlights: • CuFe{sub 2}O{sub 4} nanocrystals were synthesized by a co-precipitation method. • Ag/CuFe{sub 2}O{sub 4} catalyst was prepared by the wetness impregnation strategy. • The structural properties of Ag/CuFe{sub 2}O{sub 4} were investigated by XRD, TEM, DRS, and XPS techniques. • Ag/CuFe{sub 2}O{sub 4} has higher photocatalytic activity. - Abstract: In this work, CuFe{sub 2}O{sub 4} nanoparticles were synthesized by a chemical co-precipitation route. The Ag/CuFe{sub 2}O{sub 4} catalyst was prepared based on the CuFe{sub 2}O{sub 4} nanoparticles by the incipient wetness impregnation strategy, which showed excellent photoelectric property and catalytic activity. The structural properties of these samples were systematically investigated by X-ray powder diffraction (XRD), transmission electronic microscopy (TEM), UV–vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) techniques. The photo-induced charge separation in the samples was demonstrated by surface photovoltage (SPV) measurement. The photocatalytic degradation of 4-CP by the Ag/CuFe{sub 2}O{sub 4} and CuFe{sub 2}O{sub 4} samples were comparatively studied under xenon lamp irradiation. The results indicate that the Ag/CuFe{sub 2}O{sub 4} sample exhibited the higher efficiency for the degradation of 4-CP.

  14. Influence of alloying effect on X-ray fluorescence parameters of Co and Cu in CoCuAg alloy films

    Science.gov (United States)

    Aylikci, Nuray Kup; Tiraşoğlu, Engin; Apaydin, Gökhan; Cengiz, Erhan; Aylikci, Volkan; Bakkaloğlu, Ömer Faruk

    2009-06-01

    In this study, K β/K α X-ray intensity ratios, σ, σ production cross-sections and ωK fluorescence yields of Co and Cu and L β/L α X-ray intensity ratios, σ, σ production cross-sections and ϖ average fluorescence yields of Ag in pure metals and in different alloy compositions were measured. In this study, alloying effects on the σ production cross-sections of Co and Cu were investigated and changes interpreted according to the rearrangement of valance state electrons and the charge transfer process between the 3d elements (Co and Cu) and Ag.

  15. Microstructure, corrosion and tribological and antibacterial properties of Ti-Cu coated stainless steel.

    Science.gov (United States)

    Jin, Xiaomin; Gao, Lizhen; Liu, Erqiang; Yu, Feifei; Shu, Xuefeng; Wang, Hefeng

    2015-10-01

    A Ti-Cu coated layer on 316L stainless steel (SS) was obtained by using the Closed Field Unbalanced Magnetron Sputtering (CFUBMS) system to improve antibacterial activity, corrosion and tribological properties. The microstructure and phase constituents of Ti-Cu coated layer were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and glow discharge optical emission spectrometry (GDOES). The corrosion and tribological properties of a stainless steel substrate, SS316L, when coated with Ti-Cu were investigated in a simulated body fluid (SBF) environment. The viability of bacteria attached to the antibacterial surface was tested using the spread plate method. The results indicate that the Ti-Cu coated SS316L could achieve a higher corrosion polarization resistance and a more stable corrosion potential in an SBF environment than the uncoated SS316L substrate. The desirable corrosion protection performance of Ti-Cu may be attributable to the formation of a Ti-O passive layer on the coating surface, protecting the coating from further corrosion. The Ti-Cu coated SS316L also exhibited excellent wear resistance and chemical stability during the sliding tests against Si3N4 balls in SBF environment. Moreover, the Ti-Cu coatings exhibited excellent antibacterial abilities, where an effective reduction of 99.9% of Escherichia coli (E.coli) within 12h was achieved by contact with the modified surface, which was attributed to the release of copper ions when the Ti-Cu coatings are in contact with bacterial solution. PMID:26093948

  16. Photoelectrochemical Properties of CuS-GeO2-TiO2 Composite Coating Electrode.

    Science.gov (United States)

    Wen, Xinyu; Zhang, Huawei

    2016-01-01

    The ITO (indium tin oxide) conductive glass-matrix CuS-GeO2-TiO2 composite coating was generated via EPD (electrophoretic deposition) and followed by a sintering treatment at 450°C for 40 minutes. Characterizations of the CuS-GeO2-TiO2 composite coating were taken by SEM (scanning electron microscope), XRD (X-ray diffraction), EDX (energy dispersive X-ray), UV-Vis DRS (ultraviolet-visible diffuse reflection spectrum), and FT-IR (Fourier transform infrared spectroscopy). Results showed that CuS and GeO2 had dispersed in this CuS-GeO2-TiO2 composite coating (mass percentages for CuS and GeO2 were 1.23% and 2.79%, respectively). The electrochemical studies (cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Tafel polarization) of this CuS-GeO2-TiO2 composite coating electrode were performed in pH = 9.51 Na2CO3-NaHCO3 buffer solution containing 0.50 mol/L CH3OH under the conditions of visible light, ultraviolet light (λ = 365 nm), and dark (without light irradiation as control), respectively. Electrochemical studies indicated that this CuS-GeO2-TiO2 composite coating electrode had better photoelectrocatalytic activity than the pure TiO2 electrode in the electrocatalysis of methanol under visible light. PMID:27055277

  17. Intermetallic compound formation at Sn-3.0Ag-0.5Cu-1.0Zn lead-free solder alloy/Cu interface during as-soldered and as-aged conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Feng-Jiang [Department of Materials Science and Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China)]. E-mail: wangfjy@yahoo.com.cn; Yu, Zhi-Shui [Department of Materials Science and Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China); Qi, Kai [Department of Materials Science and Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China)

    2007-07-12

    Intermetallic formations of Sn-3.0Ag-0.5Cu solder alloy with additional 1.0 wt% Zn were investigated for Cu-substrate during soldering and isothermal aging. During soldering condition, the Cu{sub 5}Zn{sub 8} compound with granular-type morphology is the interfacial IMC for Sn-3.0Ag-0.5Cu-1.0Zn solder, while the Cu{sub 6}Sn{sub 5} compound with scallop-type morphology is the interfacial IMC for Sn-3.0Ag-0.5Cu solder. During thermal aging, the final interfacial structure for Sn-3.0Ag-0.5Cu-1.0Zn solder is solder/Cu{sub 5}Zn{sub 8}/Cu{sub 6}Sn{sub 5}/Cu{sub 3}Sn/Cu, different from the solder/Cu{sub 6}Sn{sub 5}/Cu{sub 3}Sn/Cu for Sn-3.0Ag-0.5Cu solder. The thickness of Cu-Sn IMC layers increases, while the thickness of Cu{sub 5}Zn{sub 8} compound layer decreases with increasing aging time due to the decomposition of the Cu{sub 5}Zn{sub 8} layer by the diffusion of Cu and Zn atoms into the solder and Cu{sub 6}Sn{sub 5} at higher aging temperature. For Sn-3.0Ag-0.5Cu-1.0Zn solder, at higher aging temperature of 150 or 175 {sup o}C, with the formation of Cu{sub 3}Sn at Cu{sub 6}Sn{sub 5}/Cu, Kirkendall voids can be observed at the interface of Cu{sub 3}Sn/Cu.

  18. In-situ synthesis of AgCu/Cu2O nanocomposite by mechanical alloying: The effect of the processing on the thermal behavior

    International Nuclear Information System (INIS)

    TG heating curves for Ag–Cu samples vs. the milling time, recorded during the heating. The samples’ mass variation is strongly dependent on the powders’ specific surface, respectively the milling time. - Highlights: • AgCu bimetallic composites reinforced by Cu2O has been studied. • The milling time influences the particle size distribution of the particles. • The thermal behavior of the mixtures has been studied by TG and DSC, in argon. • Correlation of thermal stability with thermal expansion properties was made. - Abstract: The influence of the mechanical alloying processing parameters on the elaboration of AgCu-based bimetallic matrix composites reinforced by in-situ synthesized Cu2O has been studied. The milling time (20, 45 and 80 h) of the initial 72% mass Ag + 28% mass Cu micrometric powders mixture influences the particle size distribution of the obtained composite particles. After 80 h of mechanical alloying, AgCu/Cu2O nanoparticles of 60–80 nm are obtained and their chemical composition at bulk/surface level has been determined by X-ray diffraction and photoelectron spectroscopy. The effect of milling time on the thermal behavior of the powders samples has been studied by thermogravimetry and differential scanning calorimetry measurements in argon atmosphere. The argon chemosorbtive reaction from the particles surface has been identified and the binding energy (0.9–1.99 eV) has been calculated. The isothermal drop calorimetry and the linear thermal expansion measurements were used to evaluate the correlation between thermal stability and thermal expansion properties of the in-situ synthesized AgCu/Cu2O nanocomposite

  19. Precipitation hardening of a Cu-free Au-Ag-Pd-In dental alloy

    International Nuclear Information System (INIS)

    The hardening mechanism and related microstructural changes of the Cu-free dental casting alloy composed of Au-Ag-Pd-In was examined by means of hardness test, X-ray diffraction (XRD), scanning electron microscopic (SEM) observations and electron probe microanalysis (EPMA). The Au-Ag-Pd-In alloy showed apparent age-hardenability. In the SEM photograph, three phases were observed in the solution-treated specimen, that is, the Au-Ag based phase with small amounts of In and Pd as matrix, the InPd phase as particle-like structures, and the Pd-rich phase as lamellar precipitates. By aging the specimen, the very fine Pd-rich inter-granular precipitates grew toward the grain interior as lamellar structure, and finally the coarsened Pd-rich precipitates covered a large part of the Au-Ag based matrix. The hardness increase in the early stage of the age-hardening process was assumed to be caused by the diffusion and aggregation of Pd atoms from the Au-Ag based matrix. The hardness decrease in the later stage of age-hardening process was caused by coarsening of the lamellar precipitates composed of the Pd-rich phase

  20. Effect of deposition of Ag on TiO{sub 2} nanoparticles on the photodegradation of Reactive Yellow-17

    Energy Technology Data Exchange (ETDEWEB)

    Rupa, A. Valentine [Department of Chemical Engineering, A.C. College of Technology, Anna University, Chennai 600025, Tamilnadu (India); Manikandan, D. [Department of Chemical Engineering, A.C. College of Technology, Anna University, Chennai 600025, Tamilnadu (India); Divakar, D. [Department of Chemical Engineering, A.C. College of Technology, Anna University, Chennai 600025, Tamilnadu (India); Sivakumar, T. [Department of Chemical Engineering, A.C. College of Technology, Anna University, Chennai 600025, Tamilnadu (India)]. E-mail: sivakumar@annauniv.edu

    2007-08-25

    Nanoparticles of TiO{sub 2} were synthesized by sol-gel technique and the photodeposition of about 1% Ag on TiO{sub 2} particles was carried out. Ag-deposited TiO{sub 2} catalyst was characterised by XRD, TEM and UV-vis spectroscopy. The Ag-TiO{sub 2} catalyst was evaluated for their photocatalytic activity towards the degradation of Reactive Yellow-17 (RY-17) under UV and visible light irradiations. Then the results were compared with synthesized nano-TiO{sub 2} sol and P-25 Degussa and the enhanced degradation was obtained with Ag-deposited TiO{sub 2}. This enhanced activity of Ag-TiO{sub 2} may be attributed to the trapping of conduction band electrons. The effect of initial dye concentration, pH and electron acceptors such as H{sub 2}O{sub 2}, K{sub 2}S{sub 2}O{sub 8} on the photocatalytic activity were studied and the results obtained were fitted with Langmuir-Hinshelwood model to study the degradation kinetics and discussed in detail.

  1. Kinetics of intermetallic phase formation at the interface of Sn-Ag-Cu-X (X = Bi, In) solders with Cu substrate

    Energy Technology Data Exchange (ETDEWEB)

    Hodulova, Erika [Institute of Production Technologies, Faculty of Materials Science and Technology, Slovak University of Technology, 91724 Trnava (Slovakia); Palcut, Marian, E-mail: marian.palcut@gmail.com [Institute of Materials Science, Faculty of Materials Science and Technology, Slovak University of Technology, 91724 Trnava (Slovakia); Lechovic, Emil; Simekova, Beata; Ulrich, Koloman [Institute of Production Technologies, Faculty of Materials Science and Technology, Slovak University of Technology, 91724 Trnava (Slovakia)

    2011-06-23

    Highlights: > In substitutes Sn in intermetallic compounds formed at the Cu-solder interface. > Bi and In decrease the parabolic rate constant of Cu{sub 3}Sn layer growth. > In increases the parabolic rate constant of Cu{sub 6}Sn{sub 5} layer growth. > High In concentrations should be avoided since they may lead to a pre-mature solder joint degradation. - Abstract: The effects of Bi and In additions on intermetallic phase formation in lead-free solder joints of Sn-3.7Ag-0.7Cu; Sn-1.0Ag-0.5Cu-1.0Bi and Sn-1.5Ag-0.7Cu-9.5In (composition given in weight %) with copper substrate are studied. Soldering of copper plate was conducted at 250 deg. C for 5 s. The joints were subsequently aged at temperatures of 130-170 deg. C for 2-16 days in a convection oven. The aged interfaces were analyzed by optical microscopy and energy dispersive X-ray spectroscopy (EDX) microanalysis. Two intermetallic layers are observed at the interface - Cu{sub 3}Sn and Cu{sub 6}Sn{sub 5}. Cu{sub 6}Sn{sub 5} is formed during soldering. Cu{sub 3}Sn is formed during solid state ageing. Bi and In decrease the growth rate of Cu{sub 3}Sn since they appear to inhibit tin diffusion through the grain boundaries. Furthermore, indium was found to produce a new phase - Cu{sub 6}(Sn,In){sub 5} instead of Cu{sub 6}Sn{sub 5}, with a higher rate constant. The mechanism of the Cu{sub 6}(Sn,In){sub 5} layer growth is discussed and the conclusions for the optimal solder chemical composition are presented.

  2. High-temperature deformation of dispersion-strengthened Cu-Zr-Ti-C alloys

    International Nuclear Information System (INIS)

    The hot mechanical behaviour and microstructure of Cu-5 vol.% TiC, Cu-5 vol.% ZrO2 and Cu-2.5 vol.% TiC-2.5 vol.% ZrO2 alloys prepared by reaction milling were studied. After a test of 1 h annealing at 1173 K, the Cu-5 vol.% ZrO2 alloy presented the lower softening resistance to annealing, while the other two ones kept their initial room-temperature hardness (about 2 GPa). Hot-compression tests at 773 and 1123 K, at initial true strain rates of 0.85 x 10-3 and 0.85 x 10-4 s-1 were performed. The Cu-2.5 vol.% TiC-2.5 vol.% ZrO2 and the Cu-5 vol.% ZrO2 alloys were the strongest and softest materials, respectively. Moreover, by electron microscopy, nanometric TiC and micrometric particles were detected in the Cu-5 vol.% TiC and Cu-5 vol.% ZrO2 alloys, respectively. A possible explanation for the observed behaviour of these materials is proposed. In the compression tests, it was also found that strain rate has a low effect on flow stress, as it has been previously observed by various authors in dispersion-strengthened alloys deformed at high temperatures

  3. Slow positrons in metal single crystals. I. Positronium formation at Ag(100), Ag(111), and Cu(111) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Lynn, K.G.; Welch, D.O.

    1980-07-01

    Monoenergetic positrons, with an incident energy of 0 --5 keV, were focused onto Ag(100), Ag(111), and Cu(111) surfaces with submonolayer contamination, and positronium formation was studied as a function of sample temperature from 300 to 1200 K. The data were fitted with a simple positron diffusion model including surface and vacancy trapping, assuming that positronium is formed only at the surface. The formation of part of the positronium fraction is found to be a temperature-activated process which is identified as detrapping from a surface state, and an estimate of the binding energy in this trap is deduced. The diffusion length is found to be only slightly temperature dependent between room temperature and the onset of vacancy trapping. At the higher sample temperatures positron trapping at thermally generated vacancies is observed by the decrease in the positron diffusion length at the higher incident voltages. A vacancy formation energy is extracted from the data and is generally found to be lower than the values obtained from bulk measurements.

  4. Electronic band structure and inter-atomic bonding in layered 1111-like Th-based pnictide oxides ThCuPO, ThCuAsO, ThAgPO, and ThAgAsO from first principles calculations

    OpenAIRE

    Bannikov, V. V.; Shein, I. R.; Ivanovskii, A. L.

    2011-01-01

    First-principles FLAPW-GGA band structure calculations were employed to examine the structural, electronic properties and the chemical bonding picture for four ZrCuSiAs-like Th-based quaternary pnictide oxides ThCuPO, ThCuAsO, ThAgPO, and ThAgAsO. These compounds were found to be semimetals and may be viewed as "intermediate" systems between two main isostructural groups of superconducting and semiconducting 1111 phases. The Th 5f states participate actively in the formation of valence bands ...

  5. Preparation and Use of Photocatalytically Active Segmented Ag|ZnO and Coaxial TiO2-Ag Nanowires Made by Templated Electrodeposition

    OpenAIRE

    Maijenburg, A.W.; Rodijk, E.J.B.; Maas, M.G.; Elshof, ten, J.E.

    2014-01-01

    Photocatalytically active nanostructures require a large specific surface area with the presence of many catalytically active sites for the oxidation and reduction half reactions, and fast electron (hole) diffusion and charge separation. Nanowires present suitable architectures to meet these requirements. Axially segmented Ag|ZnO and radially segmented (coaxial) TiO2-Ag nanowires with a diameter of 200 nm and a length of 6-20 µm were made by templated electrodeposition within the pores of pol...

  6. Creep behavior of near-peritectic Sn-5Sb solders containing small amount of Ag and Cu

    International Nuclear Information System (INIS)

    Research highlights: → We add small amount of Ag and Cu into the Sn-5Sb solder alloy. → We examine changes in the microstructure and creep properties of the solder alloys. → The Sn-5Sb-0.7Cu solder alloy shows the highest creep resistance compared with the other two alloys. → The presence of hard Cu6Sn5 and fine SbSn IMCs in the Sn-5Sb-0.7Cu alloy increased the resistance to dislocation movement, and improved the creep properties. - Abstract: Sn-5%Sb is one of the materials considered for replacing Pb-bearing alloys in electronic packaging. In the present study, the effects of minor additives of Ag and Cu on the as-cast microstructure and creep properties of the Sn-5Sb solder alloy are investigated by means of optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscope (EDS) and tensile tests. Results show that addition of Ag and Cu resulted not only in the formation of new Ag3Sn and Cu6Sn5 intermetallic compounds (IMCs), but also in the refinement of the grain size of Sn-5Sb solder. Accordingly, the creep properties of the Ag or Cu-containing solder alloys are notably improved. Attention has been paid to the role of IMCs on creep behavior. The lead-free Sn-5Sb-0.7Cu solder shows superior creep performance over the other two solders in terms of much higher creep resistance and vastly elongated creep fracture lifetime. An analysis of the creep behavior at elevated temperatures suggested that the presence of hard Cu6Sn5 and fine SbSn IMCs in the Sn-5Sb-0.7Cu alloy increases the resistance to dislocation movement, which improves the creep properties.

  7. Formation of the heavy fermion ground state in UPt4M1, M=Au, Ag, Cu

    International Nuclear Information System (INIS)

    Based on comparisons of the low temperature specific heat and susceptibility of single phase UPt4M1, where M=Au0.5Pt0.5, Au0.7Ag0.3, Au0.5Ag0.5, Au0.7Cu0.3, and Au0.5Cu0.5, it is found that the formation of large m* in this system is essentially just as dependent on subtle differences of the electronic properties of Au and Ag as on lattice parameter and Pt versus Au differences. ((orig.))

  8. Preparation, characterization and performance of Ti1-xAlxN/Ag/Ti1-xAlxN low-emissivity films

    Science.gov (United States)

    Huang, Jiamu; Xiang, Chengjie; Li, Shaohui; Zhao, Xiaoli; He, Guoqing

    2014-02-01

    In this paper, Ti1-xAlxN/Ag/Ti1-xAlxN sandwich structure low-emissivity (Low-E) films were prepared by radio frequency reactive magnetron sputtering (RF-MS) on glass substrates. The morphology, chemical state and performance of the film system were characterized by FIB-SEM, XPS, FT-IR, UV-vis spectrophotometer and electrochemical workstation. The results showed that the multilayer films exhibit an excellent visible light transmittance (T% > 85% at λ = 550 nm) and remarkable high infrared reflectivity (R% > 96% in the 2.5 ˜ 25 μm range). The Ti1-xAlxN dielectric-layer could not only increase transmittance in the visible light range of Ag film based on an anti-reflection effect, but also modify the intrinsic color of Ag film from sapphire to total color neutrality. In addition, Ti1-xAlxN layer could enhance the chemical stability of the Ag film. In principle, the approach to obtain Ti1-xAlxN/Ag/Ti1-xAlxN sandwich structure in our work could provide an alternative way to fabricate outstanding Low-E films.

  9. Preparation, Characterization, and Photocatalytic Property of CuO-TiO Nanocomposites

    Directory of Open Access Journals (Sweden)

    Longfeng Li

    2012-01-01

    Full Text Available The Cu2O-TiO2 nanocomposites were successfully synthesized by the homogeneous hydrolysation, followed by the solvothermal crystallization and ethylene glycol-thermal reduction process, respectively. The obtained products were characterized by means of X-ray diffraction(XRD, Uv-vis diffuse reflectance spectroscopy, laser particle size analysis, and scanning electron microscopy (SEM, respectively. The photocatalytic performance of Cu2O-TiO2 nanocomposites was evaluated by the degradation of methyl orange (MO as a model compound. The experimental results showed that the prepared Cu2O-TiO2 nanocomposite exhibited higher photocatalytic activity for the decomposition of MO than the pure Cu2O and the commercial Degussa P25 TiO2 under visible light irradiation.

  10. Partial and integral enthalpies of mixing of Cu-Fe-Ti melts at 1873 K

    Science.gov (United States)

    Abdulov, A. R.; Dreval', L. A.; Agraval, P. G.; Turchanin, M. A.

    2009-10-01

    The partial enthalpy of mixing of titanium in Cu-Fe-Ti melts are studied by high-temperature isoperibolic calorimetry at 1873 K in the composition range x Ti = 0-0.6 along three sections with a ratio x Fe / x Cu = 1/3, 1, and 3. The integral enthalpy of mixing of the ternary melts is calculated by integrating the Gibbs-Duhem equation and is described in terms of the Redlich-Kister-Muggianu model. Function Δ H demonstrates negative values over a wide concentration range. The contribution of a ternary interaction to the enthalpy of mixing of Cu-Fe-Ti melts is mainly positive. The first partial enthalpies of mixing of Al, Sn, Si, Y, Zr, Hf, and Ni with Cu-Fe-Ti melts are negative and indicate an increase of the thermodynamic stability of the liquid phase upon the dissolution of these additions.

  11. Quasi-Instantaneous Bacterial Inactivation on Cu-Ag Nanoparticulate 3D Catheters in the Dark and Under Light: Mechanism and Dynamics.

    Science.gov (United States)

    Rtimi, Sami; Sanjines, Rosendo; Pulgarin, Cesar; Kiwi, John

    2016-01-13

    The first evidence for Cu-Ag (50%/50%) nanoparticulate hybrid coatings is presented leading to a complete and almost instantaneous bacterial inactivation in the dark (≤5 min). Dark bacterial inactivation times on Cu-Ag (50%/50%) were observed to coincide with the times required by actinic light irradiation. This provides the evidence that the bimetal Cu-Ag driven inactivation predominates over a CuO/Cu2O and Ag2O oxides inducing a semiconductor driven behavior. Cu- or Ag-coated polyurethane (PU) catheters led to bacterial inactivation needing about ∼30 min. The accelerated bacterial inactivation by Cu-Ag coated on 3D catheters sputtered was investigated in a detailed way. The release of Cu/Ag ions during bacterial inactivation was followed by inductively coupled plasma mass-spectrometry (ICP-MS) and the amount of Cu and Ag-ions released were below the cytotoxicity levels permitted by the sanitary regulations. By stereomicroscopy the amount of live/dead cells were followed during the bacterial inactivation time. By Fourier transform infrared spectroscopy (FTIR), the systematic shift of the -(CH2) band stretching of the outer lipo-polysaccharide bilayer (LPS) was followed to monitor the changes leading to cell lysis. A hydrophobic to hydrophilic transformation of the Cu-Ag PU catheter surface under light was observed within 30 min followed concomitantly to a longer back transformation to the hydrophobic initial state in the dark. Physical insight is provided for the superior performance of Cu-Ag films compared to Cu or Ag films in view of the drastic acceleration of the bacterial inactivation observed on bimetal Cu-Ag films coating PU catheters. A mechanism of bacterial inactivation is suggested that is consistent with the findings reported in this study. PMID:26699928

  12. Effect of Erbium on the Photocatalytic Activity of TiO2 /Ag Nanocomposites under Visible Light Irradiation.

    Science.gov (United States)

    Prakash, Natarajan; Karthikeyan, Rajan; Thangaraju, Dheivasigamani; Navaneethan, Mani; Arivanandhan, Mukannan; Koyama, Tadanobu; Hayakawa, Yasuhiro

    2015-10-01

    Erbium co-doped TiO2 /Ag catalysts are synthesized by using a simple, one-step solvothermal method and characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, Raman analysis, X-ray photoelectron spectroscopy, and diffuse reflectance spectroscopy. The catalysts exhibit anatase crystal structures with increased visible light absorption compared with pure TiO2 . Enhanced photocatalytic activity is observed with Er co-doped TiO2 /Ag nanocomposites for Rhodamine B degradation under visible light irradiation. The photocatalytic activity of 1 % Er co-doped TiO2 /Ag is much higher than that of TiO2 /Ag, TiO2 /Er, pure TiO2 , and commercial Degussa P25. The kinetics of the degradation process are studied and the pseudo-first-order rate constant (k) and half-life time (t1/2 ) of the reaction are calculated. The enhanced activity might be accredited to the efficient separation of electron-hole pairs by silver and higher visible light absorption of TiO2 induced by Er. PMID:26274932

  13. Interplay of dopants and defects in making Cu doped TiO{sub 2} nanoparticle a ferromagnetic semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Choudhury, Biswajit, E-mail: biswa.tezu@gmail.com [Department of Physics, Tezpur University, Napaam 784028, Assam (India); Choudhury, Amarjyoti [Department of Physics, Tezpur University, Napaam 784028, Assam (India); Borah, Debajit [Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam (India)

    2015-10-15

    Here we have studied the role of oxygen defects and Cu dopants on ferromagnetism in Cu doped TiO{sub 2} nanoparticles with nominal Cu concentration of 2%, 4% and 6 mol%. Electron paramagnetic resonance (EPR) spectra analysis reveals the presence of Cu{sup 2+} in the distorted octahedral coordination of TiO{sub 2}. Cu d-states undergo strong p-d coupling with the valence band O 2p state of TiO{sub 2} resulting the extended absorption hump in the visible region. Photoluminescence results reveal the presence of oxygen defect related emission peaks in Cu doped TiO{sub 2}. Room temperature ferromagnetism is observed in all the Cu doped TiO{sub 2} nanoparticles. Saturation magnetization is the highest at 4 mol% and then there is a decrease in magnetization at 6 mol%. Ferromagnetism completely disappears on calcinations of 4% Cu doped TiO{sub 2} in air at 450 °C for 8 h. It is speculated that both oxygen vacancies and Cu d-states are involved in the room temperature ferromagnetism. Spin polarization occurs by the formation of bound magnetic polaron between electrons in Cu{sup 2+}d-states and the unpaired spins in oxygen vacancies. Presence of Cu{sup 2+}-Cu{sup 2+}d-d exchange interaction and Cu{sup 2+}-O{sup 2−}-Cu{sup 2+} antiferromagnetic superexchange interactions might have resulted in the reduction in magnetization at 6 mol% Cu. - Graphical abstract: Ferromagnetism in Cu doped TiO{sub 2} requires presence of both Cu dopant and oxygen vacancies. - Highlights: • Cu doped TiO{sub 2} nanoparticle displays room temperature ferromagnetism. • Ferromagnetism requires presence of both Cu and oxygen vacancies. • Antiferromagnetic interaction persists at high Cu dopant concentration. • Paramagnetism appears on air annealing of the doped system for longer period.

  14. High mobility of the strongly confined hole gas in AgTaO3/SrTiO3

    International Nuclear Information System (INIS)

    A theoretical study of the two-dimensional hole gas at the (AgO)-/(TiO2)0 p-type interface in the AgTaO3/SrTiO3(001) heterostructure is presented. The Ag 4d states strongly hybridize with the O 2p states and contribute to the hole gas. It is demonstrated that the holes are confined to an ultra thin layer (∝ 4.9 Aa) with a considerable carrier density of ∝ 1014 cm-2. We estimate a hole mobility of 18.6 cm2V-1s-1, which is high enough to enable device applications.

  15. Phase constitution and interface structure of nano-sized Ag-Cu/AlN multilayers: Experiment and ab initio modeling

    International Nuclear Information System (INIS)

    Nano-sized Ag-Cu8nm/AlN10nm multilayers were deposited by reactive DC sputtering on α-Al2O3(0001) substrates. Investigation of the phase constitution and interface structure of the multilayers evidences a phase separation of the alloy sublayers into nanosized grains of Ag and Cu. The interfaces between the Ag grains and the quasi-single-crystalline AlN sublayers are semi-coherent, whereas the corresponding Cu/AlN interfaces are incoherent. The orientation relationship between Ag and AlN is constant throughout the entire multilayer stack. These observations are consistent with atomistic models of the interfaces as obtained by ab initio calculations.

  16. Microstructure and mechanical properties of Al-Cu-Mg-Mn-Zr alloy with trace amounts of Ag

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiaoyan, E-mail: x918y@126.com [School of Material Science and Engineering, Central South University, Changsha 410083 (China); Pan Qinglin [School of Material Science and Engineering, Central South University, Changsha 410083 (China); Lu Congge [The 13th Research Institute, China Electronics Technology Company, Shijiazhuang 050000 (China); He Yunbin; Li Wenbin; Liang Wenjie [School of Material Science and Engineering, Central South University, Changsha 410083 (China)

    2009-11-15

    The microstructure and mechanical properties of Al-Cu-Mg-(Ag)-Mn-Zr alloys were studied by means of tensile testing, optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that small additions of Ag to Al-Cu-Mg-Mn-Zr alloy can accelerate the hardening effect of the aged alloy and reduce the time to peak-aged. The mechanical properties can be improved both at room temperature and at elevated temperatures, which is attributed to the fine and uniform plate-like {Omega} precipitates. Meanwhile the ductility of the studied alloys remains at relatively high level. The major strengthening phases of the Ag-free alloy are {theta}' and less S', while that of Al-Cu-Mg-Mn-Zr alloy containing trace amounts of Ag are {Omega} and less {theta}'.

  17. Microstructure and mechanical properties of Al-Cu-Mg-Mn-Zr alloy with trace amounts of Ag

    International Nuclear Information System (INIS)

    The microstructure and mechanical properties of Al-Cu-Mg-(Ag)-Mn-Zr alloys were studied by means of tensile testing, optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that small additions of Ag to Al-Cu-Mg-Mn-Zr alloy can accelerate the hardening effect of the aged alloy and reduce the time to peak-aged. The mechanical properties can be improved both at room temperature and at elevated temperatures, which is attributed to the fine and uniform plate-like Ω precipitates. Meanwhile the ductility of the studied alloys remains at relatively high level. The major strengthening phases of the Ag-free alloy are θ' and less S', while that of Al-Cu-Mg-Mn-Zr alloy containing trace amounts of Ag are Ω and less θ'.

  18. Preparation, Characterization, and Photocatalytic Property of CuO-TiO Nanocomposites

    OpenAIRE

    Longfeng Li; Maolin Zhang

    2012-01-01

    The Cu2O-TiO2 nanocomposites were successfully synthesized by the homogeneous hydrolysation, followed by the solvothermal crystallization and ethylene glycol-thermal reduction process, respectively. The obtained products were characterized by means of X-ray diffraction(XRD), Uv-vis diffuse reflectance spectroscopy, laser particle size analysis, and scanning electron microscopy (SEM), respectively. The photocatalytic performance of Cu2O-TiO2 nanocomposites was evaluated by the degrad...

  19. Ion beam mixing in binary amorphous metallic alloys. [Cu-Er; Ni-Ti

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, H.; Averback, R.S.; Diaz de la Rubia, T.; Okamoto, P.R.

    1985-12-01

    Ion beam mixing (IM) was measured in homogeneous amorphous metallic alloys of Cu-Er and Ni-Ti as a function of temperature using tracer impurities, i.e., the so-called ''marker geometry''. In Cu-Er, a strong temperature dependence in IM was observed between 80 and 373K, indicating that radiation-enhanced diffusion mechanisms are operative in this metallic glass. Phase separation of the Cu-Er alloy was also observed under irradiation as Er segregated to the vacuum and SiO2 interfaces of the specimen. At low-temperatures, the amount of mixing in amorphous Ni-Ti is similar to that in pure Ni or Ti, but it is much greater in Cu-Er than in either Cu or Er.

  20. Synthesis and characterization of carbon nanotubes-treated Ag@TiO2 core-shell nanocomposites with highly enhanced photocatalytic performance

    Science.gov (United States)

    An, Yang; Yang, Liu; Hou, Juan; Liu, Zhiyong; Peng, Banghua

    2014-06-01

    The monodispersed, uniform Ag@TiO2 core-shell nanoparticles were successfully synthesized using Ag nanoparticles as colloid seeds and tetrabutyl titanate (TBOT) as Ti source through the simple solvothermal process. The acid vapor treated multi-walled carbon nanotubes (CNTs) were introduced into Ag@TiO2 core-shell system to obtain CNTs-loaded Ag@TiO2 nanocomposites (CNTs-Ag@TiO2) through a simple dipping method. Characterization of the composites was performed using Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and High-resolution TEM (HRTEM), Energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS) and the X-ray photoelectron spectroscopy (XPS). Photocatalytic property of CNTs-Ag@TiO2 nanocomposites was investigated by photodegradation methylene blue (MB) solution under Xenon arc lamp and compared with Ag@TiO2, TiO2 and CNTs-TiO2 nanoparticles. The result showed that the photocatalysis property of CNTs-Ag@TiO2 nanocomposites was higher than other comparative particles. The presence of CNTs in the Ag@TiO2 nanocomposites could enhance the photocatalytic property owing to CNTs were good electron acceptors, can accept the excited electrons photo-initiated in the TiO2 particles and the Fermi level of the Ag is situated close to the conduction band edge of TiO2. Thus the electrons excited into the conduction band of TiO2 by UV-visible light irradiation are transferred to the surface of CNTs and Ag core easily. Therefore, recombination time of the electron-hole pair was prolonged, which was the key of enhance the photocatalytic activity.

  1. Ordering of the β phase in TiNiCu and TiNiCuMn melt spun ribbons studied with the ALCHEMI technique

    International Nuclear Information System (INIS)

    Ti-25Ni-25Cu and Ti-25Ni-23Cu-2Mn (at.%) ribbons were melt spun at 26 m s-1. Transmission electron microscopy (TEM) investigations proved that the Mn addition lowers the amount and reduces the size of the β phase crystallites present in the otherwise amorphous matrix. The observations using the (1 0 0) superlattice spot proved that each crystallite forms a single antiphase domain. The planar ALCHEMI experiments at (0 0 0, 1 0 0) orientation of thin foils from as-spun ribbons confirmed a high occupancy of the Ni-rich planes by Cu and Mn additions. However, even as practically all Mn atoms found their places on the Ni-rich planes, though a small amount of Cu atoms still occupy the planes characteristic for Ti atoms. The transfer of the remaining Cu atoms from Ti {1 0 0} to Ni {1 0 0} planes might be the reason of the rise of the temperature of the start of the martensite transformation (Ms) during further heat treatment

  2. Effect of extrusion processing on the microstructure, mechanical properties, biocorrosion properties and antibacterial properties of Ti-Cu sintered alloys.

    Science.gov (United States)

    Zhang, Erlin; Li, Shengyi; Ren, Jing; Zhang, Lan; Han, Yong

    2016-12-01

    Ti-Cu sintered alloys, Ti-Cu(S) alloy, have exhibited good anticorrosion resistance and strong antibacterial properties, but low ductility in previous study. In this paper, Ti-Cu(S) alloys were subjected to extrusion processing in order to improve the comprehensive property. The phase constitute, microstructure, mechanical property, biocorrosion property and antibacterial activity of the extruded alloys, Ti-Cu(E), were investigated in comparison with Ti-Cu(S) by X-ray diffraction (XRD), optical microscopy (OM), scanning electronic microscopy (SEM) with energy disperse spectroscopy (EDS), mechanical testing, electrochemical testing and plate-count method in order to reveal the effect of the extrusion process. XRD, OM and SEM results showed that the extrusion process did not change the phase constitute but refined the grain size and Ti2Cu particle significantly. Ti-Cu(E) alloys exhibited higher hardness and compressive yield strength than Ti-Cu(S) alloys due to the fine grain and Ti2Cu particles. With the consideration of the total compressive strain, it was suggested that the extrusion process could improve the ductility of Ti-Cu alloy(S) alloys. Electrochemical results have indicated that the extrusion process improved the corrosion resistance of Ti-Cu(S) alloys. Plate-count method displayed that both Ti-Cu(S) and Ti-Cu(E) exhibited strong antibacterial activity (>99%) against S. aureus. All these results demonstrated that hot forming processing, such as the extrusion in this study, refined the microstructure and densified the alloy, in turn improved the ductility and strength as well as anticorrosion properties without reduction in antibacterial properties. PMID:27612770

  3. Interface interaction and wetting of Sc2O3 exposed to Cu-Al and Cu-Ti melts

    International Nuclear Information System (INIS)

    Scandia is a thermodynamically stable oxide and could be used as a structural material for a crucible in order to avoid a melt contamination. In the present study wetting experiments of Cu-Al and Cu-Ti melts on Scandia substrate were preformed at 1423 K by a sessile drop method. It was established that Al and Ti additions lead to the improved wetting and that the final contact angle decreases with increasing the additives concentration. For Al containing melts, the contact angle changes gradually with time, and a relatively thick interaction layer, which consists of Al2O3, Sc2O3, and metallic channels, was formed at the Sc2O3/Cu-Al interface. For Ti containing melts, the final contact angle is achieved already during heating, and an extremely thin layer based on a Ti-Sc-O compound was detected by AES at the Sc2O3/Cu-Ti interface. The results of a thermodynamic analysis, which takes into account the formation free energy of the oxides, involved in the systems, and the thermodynamic properties of the liquid solutions are in a good agreement with the experimental observations. (orig.)

  4. Preparation and Microstructure of Cu/Ti3SiC2 Nanocomposite

    Institute of Scientific and Technical Information of China (English)

    GU Wan-li; SHENG Wen-bin; CHEN Zong-min

    2006-01-01

    Mixed micron-sized Cu/Ti3SiC2 (vol5%) powder was mechanically milled using agate balls and zirconia balls separately. Then followed an examination of it with the FEI-SEM. The experimental results show that, distributed homogenously in Cu matrix, the Ti3SiC2 particles have a size of about 30-50 nm after milled with agate balls for 8 h, while it remains approximately unchanged after milled with zirconia balls. The microstructure of the mixture at different ball-milling stages was also studied. Bulks of Cu/Ti3SiC2 nano-composite were fabricated by hot pressing nano-sized Cu/Ti3SiC2 powder at the temperature of 1 073 K under 100 MPa. Then came an investigation of the effects of the particle size and agglomerate state of Ti3SiC2 as well as the microstructure of Cu/Ti3SiC2 nano-composite. It was found that the nano-sized Ti3SiC2 particles distribute evenly in copper.

  5. Physical and chemical characterization of Ag-doped Ti coatings produced by magnetron sputtering of modular targets

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Tobias [Department for Functional Materials in Medicine and Dentistry, School of Dentistry, University of Würzburg, Pleicherwall 2, 97070 Würzburg (Germany); Institute of Tissue Engineering and Regenerative Medicine, University Hospital of the Julius-Maximilians University, Röntgenring 11, 97070 Würzburg (Germany); Warmuth, Franziska [Department for Functional Materials in Medicine and Dentistry, School of Dentistry, University of Würzburg, Pleicherwall 2, 97070 Würzburg (Germany); Werner, Ewald; Hertl, Cornelia [Institute of Materials Science and Mechanics of Materials, Technical University of Munich, Boltzmannstrasse 15, 85748 Garching (Germany); Groll, Jürgen; Gbureck, Uwe [Department for Functional Materials in Medicine and Dentistry, School of Dentistry, University of Würzburg, Pleicherwall 2, 97070 Würzburg (Germany); Moseke, Claus, E-mail: claus.moseke@fmz.uni-wuerzburg.de [Department for Functional Materials in Medicine and Dentistry, School of Dentistry, University of Würzburg, Pleicherwall 2, 97070 Würzburg (Germany)

    2014-11-01

    Silver-doped Ti films were produced using a single magnetron sputtering source equipped with a titanium target containing implemented silver modules under variation of bias voltage and substrate temperature. The Ti(Ag) films were characterized regarding their morphology, contact angle, phase composition, silver content and distribution as well as the elution of Ag{sup +} ions into cell media. SEM and AFM pictures showed that substrate heating during film deposition supported the formation of even and dense surface layers with small roughness values, an effect that could even be enforced, when a substrate bias voltage was applied instead. The deposition of both Ti and Ag was confirmed by X-ray diffraction. ICP-MS and EDX showed a clear correlation between the applied sputtering parameters and the silver content of the coatings. Surface-sensitive XPS measurements revealed that higher substrate temperatures led to an accumulation of Ag in the near-surface region, while the application of a bias voltage had the opposite effect. Additional elution measurements using ICP-MS showed that the release kinetics depended on the amount of silver located at the film surface and hence could be tailored by variation of the sputter parameters. - Highlights: • Modular targets were used to deposit Ti(Ag) films. • Ag-content is adjustable by bias voltage, sputtering power and substrate temperature. • Coating parameters significantly change film morphology and roughness. • A critical parameter for Ag release is the fraction of silver on the film surface.

  6. Physical and chemical characterization of Ag-doped Ti coatings produced by magnetron sputtering of modular targets

    International Nuclear Information System (INIS)

    Silver-doped Ti films were produced using a single magnetron sputtering source equipped with a titanium target containing implemented silver modules under variation of bias voltage and substrate temperature. The Ti(Ag) films were characterized regarding their morphology, contact angle, phase composition, silver content and distribution as well as the elution of Ag+ ions into cell media. SEM and AFM pictures showed that substrate heating during film deposition supported the formation of even and dense surface layers with small roughness values, an effect that could even be enforced, when a substrate bias voltage was applied instead. The deposition of both Ti and Ag was confirmed by X-ray diffraction. ICP-MS and EDX showed a clear correlation between the applied sputtering parameters and the silver content of the coatings. Surface-sensitive XPS measurements revealed that higher substrate temperatures led to an accumulation of Ag in the near-surface region, while the application of a bias voltage had the opposite effect. Additional elution measurements using ICP-MS showed that the release kinetics depended on the amount of silver located at the film surface and hence could be tailored by variation of the sputter parameters. - Highlights: • Modular targets were used to deposit Ti(Ag) films. • Ag-content is adjustable by bias voltage, sputtering power and substrate temperature. • Coating parameters significantly change film morphology and roughness. • A critical parameter for Ag release is the fraction of silver on the film surface

  7. Contributions of Ag Nanowires to the Photoelectric Conversion Efficiency Enhancement of TiO2 Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Liu, Yunyu; She, Guangwei; Qi, Xiaopeng; Mu, Lixuan; Wang, Xuesong; Shi, Wensheng

    2015-09-01

    Ag nanowires (AgNWs) were employed in mesoporous TiO2 dye-sensitized solar cells (DSSCs) to enhance the photoelectric conversion efficiency (PCE). The possible reasons for PCE improvement, i.e., improvement in electron transport and light harvesting due to light scattering and plasmonic resonance effect of AgNWs are investigated. Electrochemical impedance spectra (EIS) study proved that addition of AgNWs can enhance the conductivity of TiO2 thin film photoanode, which is an important reason for the increase of photocurrent. Furthermore, through the comparison experiments as well as the UV-Vis absorption and IPCE characterization, contributions of the light scattering and plasmonic resonance effect to the enhancement of light harvest, and thus PCE of the DSSCs were demonstrated. It was found that fast electron transport of AgNWs played more important role for the PCE improvement than the light harvest enhancement due to light scattering and plasmonic effect. Based on these investigations, the AgNWs modified TiO2 thin film DSSCs were optimized. After integrating AgNWs into the photoanode, the photocurrent increased significantly and PCE increased -50% comparing with the pure TiO2-based DSSCs. PMID:26716285

  8. Transparent ITO/Ag-Pd-Cu/ITO multilayer cathode use in inverted organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyo-Joong; Kim, Han-Ki, E-mail: imdlhkkim@khu.ac.kr [Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, 1 Seocheon-dong, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of); Lee, Hyun Hwi [Pohang Accelerator Laboratory, POSTECH, Jigokro-127beon-gil, Nam-gu, Pohang 790-784 (Korea, Republic of); Kal, Jinha; Hahn, Jungseok [Future Technology Research Group, Kolon Central Research Park, 154 Mabukro, Giheung-ku, Yongin-si, Kyunggi-do, 16910 (Korea, Republic of)

    2015-10-15

    The characteristics of transparent ITO/Ag-Pd-Cu (APC)/ITO multilayer cathodes were investigated for use in inverted organic solar cells (IOSCs). The insertion of an APC interlayer into the ITO film effectively led to crystallization of the top ITO layer, unlike that in the Ag interlayer, and resulted in a low sheet resistance of 6.55 Ohm/square and a high optical transmittance of 84.14% without post annealing. In addition, the alloying of the Pd and Cu elements into Ag prevented agglomeration and oxidization of the metal interlayer and led to more stable ITO/APC/ITO films under ambient conditions. The microstructure and interfacial structure of the transparent ITO/APC/ITO cathode in the IOSCs were examined in detail by synchrotron X-ray scattering and high resolution transmission electron microscopy. Furthermore, we suggested a possible mechanism to explain the lower PCE of the IOSCs with an ITO/APC/ITO cathode than that of a reference IOSC with a crystalline ITO cathode using the external quantum efficiency of the IOSCs.

  9. Transparent ITO/Ag-Pd-Cu/ITO multilayer cathode use in inverted organic solar cells

    Science.gov (United States)

    Kim, Hyo-Joong; Lee, Hyun Hwi; Kal, Jinha; Hahn, Jungseok; Kim, Han-Ki

    2015-10-01

    The characteristics of transparent ITO/Ag-Pd-Cu (APC)/ITO multilayer cathodes were investigated for use in inverted organic solar cells (IOSCs). The insertion of an APC interlayer into the ITO film effectively led to crystallization of the top ITO layer, unlike that in the Ag interlayer, and resulted in a low sheet resistance of 6.55 Ohm/square and a high optical transmittance of 84.14% without post annealing. In addition, the alloying of the Pd and Cu elements into Ag prevented agglomeration and oxidization of the metal interlayer and led to more stable ITO/APC/ITO films under ambient conditions. The microstructure and interfacial structure of the transparent ITO/APC/ITO cathode in the IOSCs were examined in detail by synchrotron X-ray scattering and high resolution transmission electron microscopy. Furthermore, we suggested a possible mechanism to explain the lower PCE of the IOSCs with an ITO/APC/ITO cathode than that of a reference IOSC with a crystalline ITO cathode using the external quantum efficiency of the IOSCs.

  10. Transparent ITO/Ag-Pd-Cu/ITO multilayer cathode use in inverted organic solar cells

    Directory of Open Access Journals (Sweden)

    Hyo-Joong Kim

    2015-10-01

    Full Text Available The characteristics of transparent ITO/Ag-Pd-Cu (APC/ITO multilayer cathodes were investigated for use in inverted organic solar cells (IOSCs. The insertion of an APC interlayer into the ITO film effectively led to crystallization of the top ITO layer, unlike that in the Ag interlayer, and resulted in a low sheet resistance of 6.55 Ohm/square and a high optical transmittance of 84.14% without post annealing. In addition, the alloying of the Pd and Cu elements into Ag prevented agglomeration and oxidization of the metal interlayer and led to more stable ITO/APC/ITO films under ambient conditions. The microstructure and interfacial structure of the transparent ITO/APC/ITO cathode in the IOSCs were examined in detail by synchrotron X-ray scattering and high resolution transmission electron microscopy. Furthermore, we suggested a possible mechanism to explain the lower PCE of the IOSCs with an ITO/APC/ITO cathode than that of a reference IOSC with a crystalline ITO cathode using the external quantum efficiency of the IOSCs.

  11. Transparent ITO/Ag-Pd-Cu/ITO multilayer cathode use in inverted organic solar cells

    International Nuclear Information System (INIS)

    The characteristics of transparent ITO/Ag-Pd-Cu (APC)/ITO multilayer cathodes were investigated for use in inverted organic solar cells (IOSCs). The insertion of an APC interlayer into the ITO film effectively led to crystallization of the top ITO layer, unlike that in the Ag interlayer, and resulted in a low sheet resistance of 6.55 Ohm/square and a high optical transmittance of 84.14% without post annealing. In addition, the alloying of the Pd and Cu elements into Ag prevented agglomeration and oxidization of the metal interlayer and led to more stable ITO/APC/ITO films under ambient conditions. The microstructure and interfacial structure of the transparent ITO/APC/ITO cathode in the IOSCs were examined in detail by synchrotron X-ray scattering and high resolution transmission electron microscopy. Furthermore, we suggested a possible mechanism to explain the lower PCE of the IOSCs with an ITO/APC/ITO cathode than that of a reference IOSC with a crystalline ITO cathode using the external quantum efficiency of the IOSCs

  12. Electron configuration and charge state of electrically active Cu, Ag and Au ions in ZnSe

    International Nuclear Information System (INIS)

    The Hall effect, electrical conductivity and electron mobility are investigated at temperatures between 55 and 500 K in n-ZnSe crystals doped with Cu, Ag or Au. The presence of a small amount of Cu atoms leads to an inversion of the sign of the Hall coefficient at temperatures above 300 K. Anomalous temperature dependence of the electron mobility is observed in the samples with low Cu concentration (Zn+ (d10) and CuZn2+ (d9), and two acceptor levels near the valence band. Silver and gold exist in single-charged states AgZn+ and AuZn+ with d10 electron configuration forming single energy levels near the valence band. Au atoms form mainly interstitial Aui donors at low doping concentrations and substitutional AuZn and AuZn-based acceptors at high doping concentrations. Time stimulation of the amphoteric properties of Ag is discussed

  13. Synthesis and properties of Cu-Zr-Ag-Al glassy alloys with high glass-forming ability

    International Nuclear Information System (INIS)

    New Cu-Zr-based glassy alloys with an unusual glass-forming ability (GFA) were synthesized in the Cu-Zr-Ag-Al system, based on a ternary Cu45Zr45Ag10 alloy. The quaternary alloys exhibit large supercooled liquid region of 75-108 K and high-reduced glass transition temperature of 0.581-0.610. The best GFA was obtained for Cu36Zr48Ag8Al8 alloy, from which bulk glassy samples of up to 25 mm diameter were successfully fabricated by an injection mold casting method. The bulk glassy alloys exhibit high-compressive fracture strength of 1836-1981 MPa with plastic strain of 0.1-1.0% and excellent corrosion resistance in 1N H2SO4 solution

  14. Numerical simulation of iron/TiC ceramic tappet brazed with TiZrNiCu filler metal

    Institute of Scientific and Technical Information of China (English)

    张丽霞; 冯吉才; 李卓然

    2003-01-01

    Maximum value of thermal stress and stress concentration zones of iron/TiC ceramic tappet during cooling were studied.The results show that when the temperature is 300 K,the maximum values of shear stress and tensile stress on iron/TiC ceramic interface both appear on the tip of TiZrNiCu/iron interface,so cracks always originate from TiZrNiCu/iron interface.Positive tensile stress on iron undersurface relaxes to the inner of iron and negative tensile stress on iron undersurface concentrates on the side of iron as the temperature declines,which leads to the origination of cracks on iron undersurface because of the alternation between positive and negative tensile stress.

  15. Fracture analysis of Ag nanobrazing of NiTi to Ti alloy

    Directory of Open Access Journals (Sweden)

    L. Quintino

    2013-09-01

    Full Text Available Dissimilar joining of shape memory alloys to Ti alloys has long been attempted by several research groups due to the foreseen potential industrial applications. However, the very dissimilar thermo-physical properties of both materials place several difficulties. Brazing can be a solution since the base materials are subjected to a less sharp thermal cycle. In the present study brazed overlap joints of 1 mm thick plates of equiatomic NiTi and Ti6Al4V were produced using nano silver based filler materials. Surfaces were analyzed to assess the type of fracture and the capability of achieving bonding and involved mechanisms are discussed.

  16. Fracture analysis of Ag nanobrazing of NiTi to Ti alloy

    Energy Technology Data Exchange (ETDEWEB)

    Quintino, L., E-mail: lquirino@ist.utl.pt [Universidade Tecnica de Lisboa (IST/UTL) (Portugal). Instituto Superior Tecnico. Dept. de Engenharia Mecanica; Liu, L., E-mail: ray.plasma@gmail.com [Tsinghua Univ., Beijing (China). Dept. of Mechanical Engineering; Hu, A.; Zhou, Y., E-mail: anming.hu@uwaterloo.ca, E-mail: nzhou@uwaterloo.ca [University of Waterloo, Ontario (Canada). Dept. of Mechanical Engineering; Miranda, R.M., E-mail: rmiranda@fct.unl.pt [Universidade Nova de Lisboa (UNIDEMI), Caparica (Portugal). Dept. de Engenharia Mecanica e Industrial

    2013-07-15

    Dissimilar joining of shape memory alloys to Ti alloys has long been attempted by several research groups due to the foreseen potential industrial applications. However, the very dissimilar thermo-physical properties of both materials place several difficulties. Brazing can be a solution since the base materials are subjected to a less sharp thermal cycle. In the present study brazed overlap joints of 1 mm thick plates of equiatomic Ni Ti and Ti6Al4V were produced using nano silver based filler materials. Surfaces were analyzed to asses the type of fracture and the capability of achieving bonding and involved mechanisms are discussed. (author)

  17. Fracture analysis of Ag nanobrazing of NiTi to Ti alloy

    International Nuclear Information System (INIS)

    Dissimilar joining of shape memory alloys to Ti alloys has long been attempted by several research groups due to the foreseen potential industrial applications. However, the very dissimilar thermo-physical properties of both materials place several difficulties. Brazing can be a solution since the base materials are subjected to a less sharp thermal cycle. In the present study brazed overlap joints of 1 mm thick plates of equiatomic Ni Ti and Ti6Al4V were produced using nano silver based filler materials. Surfaces were analyzed to asses the type of fracture and the capability of achieving bonding and involved mechanisms are discussed. (author)

  18. Experimental and theoretical determination of cross sections and rate constants for charge transfer population of some excited Ag+, I+, and Cu+ levels

    Science.gov (United States)

    Temelkov, K. A.; Vuchkov, N. K.; Sabotinov, N. V.

    2007-04-01

    Cross-sections and rate constants for thermal energy charge transfer into some Ag+, I+, and Cu+ excited states are theoretically and experimentally obtained for a gas discharge in the He-CuBr, Ne-CuBr, He-AgI, and Ne-AgI mixtures. Besides the pumping process the formation of the inversion population is determined by the radiative transitions, which populate or depopulate the upper and lower laser levels.

  19. Effect of rare earth Ce on the fatigue life of SnAgCu solder joints in WLCSP device using FEM and experiments

    International Nuclear Information System (INIS)

    With the addition of 0.03 wt% rare earth Ce, in our previous works, the properties of SnAgCu solder were enhanced obviously. Based on the Garofalo–Arrhenius creep constitutive model, finite element method was used to simulate the stress–strain response during thermal cycle loading, and combined with the fatigue life prediction models, the fatigue life of SnAgCu/SnAgCuCe solder joints was calculated respectively, which can demonstrate the effect of the rare earth Ce on the fatigue life of SnAgCu solder joints. The results indicated that the maximum stress–strain can be found on the top surface of the corner solder joint, and the warpage of the PCB substrate occurred during thermal cycle loading. The trends obtained from modeling results have a good agreement with the experimental data reported in the literature for WLCSP devices. In addition, the stress–strain of SnAgCuCe solder joints is lower than that of SnAgCu solder joints. The thermal fatigue lives of solder joints calculated based on the creep model and creep strain energy density model show that the fatigue life of SnAgCuCe solder joints is higher than the SnAgCu solder joints. The fatigue life of SnAgCuCe solder joints can be enhanced significantly with the addition of Ce, is 30.2% higher than that of SnAgCu solder joints, which can be attributed to the CeSn3 particles formed resisting the motion of dislocation; moreover, the refinement of microstructure and the IMC sizes also contribute to the enhancement of fatigue life, which elucidates that SnAgCuCe solder can be utilized in electronic industry with high reliability replacing the SnAgCu solder

  20. Synthesis of Ag-doped TiO2 nanoparticles by combining laser decomposition of titanium isopropoxide and ablation of Ag for dye-sensitized solar cells

    Science.gov (United States)

    Al-Kamal, Ahmed Kamal

    Nanostructured powders of TiO2 and Ag-doped TiO2 are synthesized by a novel pulsed-laser process that combines laser ablation of a silver (Ag) disc with laser decomposition of a titanium tetra-isopropoxide (TTIP) solution. Nanoparticles are formed by rapid condensation of vaporized species in the plasma plume generated by the high power laser, resulting in the formation of rapidly quenched Ag-doped TiO2 nanoparticles that have far-from-equilibrium or metastable structures. The uniqueness of the new ablation process is that it is a one-step process, in contrast to the two-step process developed by previous researchers in the field. Moreover, its ability to synthesize an extended-solid solution phase of Ag in TiO 2 may also be unique. The present work implies that other oxide phases, such as Al2O3, MgO and MgAl2O4, can be doped with normally insoluble metals, such as Pt and Ir, thus opening new opportunities for catalytic applications. Again, there is the prospect of being able to synthesize nanopowders of diamond, c-BN, and mixtures thereof, which are of interest for applications in machine tools, rock-drill bits, and lightweight armor. A wet-chemistry method is also investigated, which has much in common with that adopted by previous workers in the field. However, photo-voltaic properties do not measure up to expectations based on published data. A possible explanation is that the selected Ag concentrations are too high, so that recombination of holes and electrons occurs via a quantum-tunneling mechanism reduces photo-activity. Future work, therefore, will investigate lower concentrations of Ag dopant in TiO2, while also examining the effects of metastable states, including extended solid solution, amorphous, and semi-crystalline structures.

  1. Modification of trace metal accumulation in the green mussel Perna viridis by exposure to Ag, Cu, and Zn

    International Nuclear Information System (INIS)

    To examine the Cd, Hg, Ag, and Zn accumulation in the green mussel Perna viridis affected by previous exposure to Cu, Ag, or Zn, the dietary metal assimilation efficiency (AE) and the uptake rate from the dissolved phase were quantified. The mussel's filtration rate, metallothionein (MT) concentration, and metal tissue burden as well as the metal subcellular partitioning were also determined to illustrate the potential mechanisms underlying the influences caused by one metal pre-exposure on the bioaccumulation of the other metals. The green mussels were pre-exposed to Cu, Ag, or Zn for different periods (1-5 weeks) and the bioaccumulation of Cd, Hg, Ag, and Zn were concurrently determined. Pre-exposure to the three metals did not result in any significant increase in MT concentration in the green mussels. Ag concentration in the insoluble fraction increased with increasing Ag exposure period and Ag ambient concentration. Our data indicated that Cd assimilation were not influenced by the mussel's pre-exposure to the three metals (Cu, Ag, and Zn), but its dissolved uptake was depressed by Ag and Zn exposure. Although Hg assimilation from food was not affected by the metal pre-exposure, its influx rate from solution was generally inhibited by the exposure to Cu, Ag, and Zn. Ag bioaccumulation was affected the most obviously, in which its AE increased with increasing Ag tissue concentration, and its dissolved uptake decreased with increasing tissue concentrations of Ag and Cu. As an essential metal, Zn bioaccumulation remained relatively stable following the metal pre-exposure, suggesting the regulatory ability of Zn uptake in the mussels. Zn AE was not affected by metal pre-exposure, but its dissolved uptake was depressed by Ag and Zn pre-exposure. All these results indicated that the influences of one metal pre-exposure on the bioaccumulation of other metals were metal-specific due to the differential binding and toxicity of metals to the mussels. Such factors should

  2. AgCuVO4 : A quasi-one-dimensional S=(1)/(2) chain compound

    Science.gov (United States)

    Möller, A.; Schmitt, M.; Schnelle, W.; Förster, T.; Rosner, H.

    2009-09-01

    We present a joint experimental and computational study of the recently synthesized spin 1/2 system silver-copper-orthovanadate AgCuVO4 [A. Möller and J. Jainski, Z. Anorg. Allg. Chem. 634, 1669 (2008)] exhibiting chains of trans corner-sharing [CuO4] plaquettes. The static magnetic susceptibility and specific heat measurements of AgCuVO4 can be described to a good approximation by the Bonner-Fisher spin-chain model with Jintra≈330K . Evidence for a Néel-type of order at ˜2.5K is obtained from the specific heat and corroborated by ESR studies. To independently obtain a microscopically based magnetic model, density functional electronic structure calculations were performed. In good agreement with the experimental data, we find pronounced one-dimensional magnetic exchange along the corner-sharing chains with small interchain couplings. The difference between the experimentally observed and the calculated ordering temperature can be assigned to a sizable interchain frustration derived from the calculations.

  3. Microstructure of Hot-Deformed Cu-3Ti Alloy

    Directory of Open Access Journals (Sweden)

    Szkliniarz A.

    2016-03-01

    Full Text Available In the paper, results of investigations regarding temperature and strain rate effects on hot-deformed Cu-3Ti alloy microstructure are presented. Evaluation of the alloy microstructure was performed with the use of a Gleeble HDS-V40 thermal-mechanical simulator on samples subjected to uniaxial hot compression within 700 to 900ºC and at the strain rate of 0.1, 1.0 or 10.0 s-1 until 70% (1.2 strain. It was found that within the analyzed temperature and strain rate ranges, the alloy deformation led to partial or complete recrystallization of its structure and to multiple refinement of the initial grains. The recrystallization level and the average diameter of recrystallized grains increase with growing temperature and strain rate. It was shown that entirely recrystallized, fine-grained alloy structure could be obtained following deformation at the strain rate of min 10.0 s-1 and the temperature of 800°C or higher.

  4. Visible-light-driven TiO2/Ag3PO4/GO heterostructure photocatalyst with dual-channel for photo-generated charges separation

    International Nuclear Information System (INIS)

    Highlights: • TiO2/Ag3PO4/GO was synthesized with a facile two-step method. • TiO2/Ag3PO4/GO exhibit superior photocatalytic activity and stability. • TiO2/Ag3PO4/GO has dual-channel for photo-generated charges separation. • TiO2/Ag3PO4/GO composite reduces the consumption of Ag. - Abstract: A novel triple-component TiO2/Ag3PO4/graphene oxide (TiO2/Ag3PO4/GO) photocatalyst with dual channels for photo-generated charges separation has been synthesized to improve the photocatalytic activity and stability of Ag3PO4 under visible light. The synthesis involved in-situ growth of Ag3PO4 nanoparticles on GO sheets to form Ag3PO4/GO, and then deposited TiO2 nanocrystals on the surface of Ag3PO4 by hydrolysis of Ti(SO4)2 at low-temperature hydrothermal condition. The TiO2/Ag3PO4/GO exhibited superior photocatalytic activity and stability to bare Ag3PO4, TiO2/Ag3PO4 and Ag3PO4/GO in degradation of Rhodamine B and phenol solutions under visible light. It is suggested that the photo-generated electrons in the conduction band of Ag3PO4 can be quickly transferred to GO, while the holes in the valence band of Ag3PO4 can be transferred to the valence band of TiO2. The dual transfer channels at the interfaces of TiO2/Ag3PO4/GO result in effective charges separation, leading to enhanced photocatalytic activity and stability. Furthermore, the content of noble metal Ag significantly reduces from 77 wt% in bare Ag3PO4 to 55 wt% in the nanocomposite. The concept of establishing dual channels for charges separation in a triple-component heterostructure provides a promising way to develop photocatalysts with high efficiency

  5. Hydrogen effect on shear modulus in TiNi-TiCu system quasibinary alloys

    International Nuclear Information System (INIS)

    The study on the quick-quenched films of the Ti50Ni25Cu25 alloys, 40-60 μm thick, saturated with hydrogen through the electrolytic facility is carried out. The crystalline, amorphous or amorphous-crystalline states were obtained in dependence on the melt cooling rate. The shear modulus was measured through the method of the torsion oscillations on the 1 Hz order frequencies. Sharp decrease in the modulus shear in the amorphous alloys was noted in the hydrogen saturation process. The conclusion is made that the observed effect is not connected with the origination of new phase and structural constituents by the hydrogen saturation and it may be explained by its superequilibrium concentration

  6. Interaction of Ag with YBa2Cu3O7-x

    International Nuclear Information System (INIS)

    The aim of the work was to investigate the effect of Ag (0.3 to 20 mass%) on the structure, the composition and some superconducting and magnetic properties of Y-HTSC. The alloys were studied by scanning electron microscopy (in secondary and elastically backscattering electron mode) and X-ray diffraction analysis (DRON-2.0; CuKα-radiation). Tc was measured by both resistive and inductive methods at T >> 77 K. The resistivity was determined by four-point technique (Ag solder) at 100 to 300 K and with 1 mA (operating current). Magnetic flux penetration was studied by a mechanical method in sound frequency interval. (orig./MM)

  7. Effect of Nb on glass forming ability and plasticity of (Ti-Cu)-based bulk metallic glasses

    International Nuclear Information System (INIS)

    A Ti33Cu47Zr9Ni6Sn2Si1Nb2 bulk metallic glass has been developed by Nb partial substitution for Zr in Ti33Cu47Zr11Ni6Sn2Si1 alloy. The glass forming ability Ti33Cu47Zr9Ni6Sn2Si1Nb2 alloy has been investigated using differential scanning calorimetry and X-ray diffractometry. Partial Nb substitutes for Zr promote the glass forming ability. Ti33Cu47Zr9Ni6Sn2Si1Nb2 BMG with diameter of 3 mm can be fabricated by Cu-mold injection casting method. The glass forming ability of Ti33Cu47Zr9Ni6Sn2Si1Nb2 alloy is enhanced by stabilizing the undercooled liquid against crystallization. The plastic strain up to 2.5% was obtained for Ti33Cu47Zr9Ni6Sn2Si1Nb2 BMG compared to 0.15% for Ti33Cu47Zr11Ni6Sn2Si1 BMG, which demonstrates that small amount of Nb addition can have a dramatic effect on plasticity enhancement in Ti-Cu-based BMG. The intersection and branching of the shear bands are observed. The plastic strain of the Ti33Cu47Zr9Ni6Sn2Si1Nb2 BMG can be improved by the generation of nanocrystalline particles, which lead to multiple shear bands.

  8. Improved photocatalytic activity of nano CuO-incorporated TiO2 granules prepared by spray drying

    Institute of Scientific and Technical Information of China (English)

    Zongjie Liu; Chungen Zhoun

    2015-01-01

    4 wt%CuO–96 wt%TiO2 granules were prepared by a spray drying process. The microstructure and optical property of CuO–TiO2 granules were studied. The results indicate that copper existed in the form of CuO. The spray dried granules possess spherical geometry and smooth surface with grain size in the range of 40–80μm. CuO–TiO2 has a relatively smaller Eg value (2.85 eV) than TiO2 (3.17 eV). The photocatalytic property of CuO–TiO2 granules was investigated by degradation of a model pollutant (the azo dye methyl orange) under the irradiation of the xenon lamp equipped with a band pass filter of 365 nm. The CuO–TiO2 spray-dried granules degrade about 10%more MO than TiO2 spray-dried granules under UV irradiation within the same time. The XPS spectra suggested that Cu2 þ and reduced copper species were coexistent in reacted CuO–TiO2 photocatalyst. The improvement of photocatalytic activity for CuO–TiO2 was mainly attributed to effective separation of photo-generated electron–hole pairs in the presence of CuO.

  9. One-Step Solvothermal Method to Prepare Ag/Cu2O Composite With Enhanced Photocatalytic Properties

    Science.gov (United States)

    Deng, Xiaolong; Wang, Chenggang; Zhou, E.; Huang, Jinzhao; Shao, Minghui; Wei, Xianqi; Liu, Xiaojing; Ding, Meng; Xu, Xijin

    2016-01-01

    Ag/Cu2O microstructures with diverse morphologies have been successfully synthesized with different initial reagents of silver nitrate (AgNO3) by a facile one-step solvothermal method. Their structural and morphological characteristics were carefully investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), and the experimental results showed that the morphologies transformed from microcubes for pure Cu2O to microspheres with rough surfaces for Ag/Cu2O. The photocatalytic activities were evaluated by measuring the degradation of methyl orange (MO) aqueous solution under visible light irradiation. The photocatalytic efficiencies of MO firstly increased to a maximum and then decreased with the increased amount of AgNO3. The experimental results revealed that the photocatalytic activities were significantly influenced by the amount of AgNO3 during the preparation process. The possible reasons for the enhanced photocatalytic activities of the as-prepared Ag/Cu2O composites were discussed.

  10. One-Step Solvothermal Method to Prepare Ag/Cu2O Composite With Enhanced Photocatalytic Properties.

    Science.gov (United States)

    Deng, Xiaolong; Wang, Chenggang; Zhou, E; Huang, Jinzhao; Shao, Minghui; Wei, Xianqi; Liu, Xiaojing; Ding, Meng; Xu, Xijin

    2016-12-01

    Ag/Cu2O microstructures with diverse morphologies have been successfully synthesized with different initial reagents of silver nitrate (AgNO3) by a facile one-step solvothermal method. Their structural and morphological characteristics were carefully investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), and the experimental results showed that the morphologies transformed from microcubes for pure Cu2O to microspheres with rough surfaces for Ag/Cu2O. The photocatalytic activities were evaluated by measuring the degradation of methyl orange (MO) aqueous solution under visible light irradiation. The photocatalytic efficiencies of MO firstly increased to a maximum and then decreased with the increased amount of AgNO3. The experimental results revealed that the photocatalytic activities were significantly influenced by the amount of AgNO3 during the preparation process. The possible reasons for the enhanced photocatalytic activities of the as-prepared Ag/Cu2O composites were discussed. PMID:26781287

  11. Effect of Ag micro-alloying on the microstructure and properties of Cu-14Fe in situ composite

    International Nuclear Information System (INIS)

    This paper studied Ag micro-alloying in the deformation-processed Cu-14Fe in situ composite, by a comparison of Cu-14Fe and Cu-14Fe-0.06Ag. Each alloy was prepared by casting and processed into an in situ composite by hot and cold working. The microstructures were documented using light microscopy and scanning electron microscopy (SEM). The mechanical properties were measured with a tensile-testing machine. The electrical conductivity was measured with a micro-ohmmeter. For both alloys, the as-cast microstructure consisted of a Cu matrix and Fe dendrites; after hot and cold working the microstructure consisted of a Cu matrix containing Fe fibres elongated in the working direction. The as-cast Ag-containing alloy contained finer Fe dendrites. The Ag-containing in situ composite had thinner Fe fibres, higher tensile strength, higher ductility, and higher conductivity. The cold worked Cu-14Fe-0.06Ag in situ composite with cumulative cold deformation strain η = 7.8 (where η = ln(A0/A) and A0 and A are the original and final cross-section areas, respectively), achieved a tensile strength of 930 MPa and a conductivity of 56%IACS (International Annealed Copper Standard; 17.241 nΩ m is defined as 100%IACS). The Ag micro-alloyed in situ composite had a combination of properties comparable to that of a much more expensive alloy containing much more Ag. After 1 h heat treatment at 300 deg. C, the tensile strength was increased to 950 MPa and the conductivity was increased to 56.4%IACS.

  12. Photoelectrochemical Properties of CuS-GeO2-TiO2 Composite Coating Electrode

    OpenAIRE

    Wen, Xinyu; Zhang, Huawei

    2016-01-01

    The ITO (indium tin oxide) conductive glass-matrix CuS-GeO2-TiO2 composite coating was generated via EPD (electrophoretic deposition) and followed by a sintering treatment at 450°C for 40 minutes. Characterizations of the CuS-GeO2-TiO2 composite coating were taken by SEM (scanning electron microscope), XRD (X-ray diffraction), EDX (energy dispersive X-ray), UV-Vis DRS (ultraviolet-visible diffuse reflection spectrum), and FT-IR (Fourier transform infrared spectroscopy). Results showed that Cu...

  13. Characteristics of Laser Reflow Bumping of Sn3.5Ag and Sn3.5Ag0.5Cu Lead-Free Solder Balls

    Institute of Scientific and Technical Information of China (English)

    Yanhong TIAN; Chunqing WANG; Yarong CHEN

    2008-01-01

    Lead-free Sn3.5Ag and Sn3.5Ag0.5Cu solder balls were reflowed by laser to form solder bumps. Shear test was performed on the solder bumps, and SEM/EDX (scanning electron microscopy/energy dispersive X-ray spectrometer) was used to analyze the formation of intermetallic compounds (IMCs) at interface region. A finite element modeling on the temperature gradient and distribution at the interface of solder bump during laser reflow process was conducted to elucidate the mechanism of the IMCs growth direction. The results show that the parameters window for laser reflow bumping of Sn3.5Ag0.5Cu was wider than that of Sn3.5Ag. The shear strength of Sn3.5Ag0.5Cu solder bump was comparable to that of Sn3.5Ag solder bump, and was not affected obviously by laser power and irradiation time when appropriate parameters were used. Both laser power and heating time had a significant effect on the formation of IMCs. A continuous AuSn4 interrnetallic compound layer and some needle-like AuSn4 were observed at the interface of solder and Au/Ni/Cu metallization layer when the laser power is small. The formation of needle-like AuSn4 was due to temperature gradient at the interface, and the direction of temperature gradient was the preferred growth direction of AuSn4. With increasing the laser power and heating time, the needle-like AuSn4 IMCs dissolved into the bulk solder, and precipitated out once again during solidification along the grain boundary of the solder bump.

  14. Effect of Yttrium on the Fracture Strength of the Sn-1.0Ag-0.5Cu Solder Joints

    Science.gov (United States)

    Choi, Hyelim; Kaplan, Wayne D.; Choe, Heeman

    2016-04-01

    This is a preliminary investigation on the mechanical properties of Pb-free Sn-1.0Ag-0.5Cu solder joints containing 0.02 wt.% to 0.1 wt.% Y under a range of thermal aging and reflow conditions. Despite the significantly thicker intermetallic compound (IMC) formed at the solder joint, the 0.1 wt.% Y-doped joint exhibited a higher fracture strength than its baseline Sn-1.0Ag-0.5Cu counterpart under most aging and reflow conditions. This may be associated with the formation of Y-Cu IMCs formed at the interface between the solder and the Cu substrate, because the Y-Cu IMCs have recently been referred to as relatively `ductile' IMCs.

  15. Messung von Diffusionskoeffizienten in ternären AlCuAg-Legierungen und deren Subsystemen

    OpenAIRE

    Engelhardt, Marc

    2014-01-01

    Within the scope of this thesis inter- as well as self-diffusion coefficients have been determined by experimental series of measurements on a ternary Al-Cu-Ag system at the eutectic as well as on the binary constituent systems. Through the design of a state of the art ex-situ long-capillary facility and combined with the application of new and complementary methods of measurement with strong enhanced precision this investigation offers a methodical approach to these systems and identifies re...

  16. Preparation of Cu, Ag, Fe and Al nanoparticles by the exploding wire technique

    Indian Academy of Sciences (India)

    P Sen; Joyee Ghosh; Alqudami Abdullah; Prashant Kumar; Vandana

    2003-10-01

    We describe a novel process for the production of nanoparticles of Cu, Ag, Fe and Al which involves exploding their respective wires, triggered by large current densities in the wires. The particles are characterised by X-ray diffraction (XRD) and atomic force microscopy (AFM). Particle sizes in the range 20-100nm were obtained employing this technique. The XRD results reveal that the nanoparticles continue to retain lattice periodicity at reduced particle sizes, displaying in some cases evidence of lattice strain and preferential orientation. In the case of Fe, Mossbauer spectroscopy reveals loss of ferromagnetism as a result of the reduced size of the particles.

  17. Wettability in the liquid Cu-Ag alloy – fireproof material – gas phase system

    Directory of Open Access Journals (Sweden)

    G. Siwiec

    2013-07-01

    Full Text Available In the present paper, results of wettability studies on the liquid metal – fireproof material – gas phase system using copper and Cu-Ag alloys as well as typical fireproof materials, i.e. aluminium oxide, magnesium oxide and graphite, are presented. Contact angle measurements were conducted at 1 373–1 573 K by means of a high-temperature microscope coupled with a camera and a computer equipped with a program for recording and analysing images. For the measurements, the sessile drop method was used.

  18. Crystal orientation and morphology in Al-Ag-Cu ternary eutectic

    OpenAIRE

    Genau, Amber L; Ratke, Lorenz

    2011-01-01

    Ternary eutectics provide a unique opportunity for studying the e�ects of complex microstructure formation, as three distinct phases must be formed simultaneously from the melt. In order to produce fully coupled three-phase growth, Al-Ag-Cu at the ternary eutectic composition was directionally solidi�ed in a constant temperature gradient of 3 K/mm at velocities between 0.2 and 5.0 �m/sec. Under these conditions, the two intermetallic phases appear to grow as closely coupled rod...

  19. In vitro study on an antibacterial Ti-5Cu alloy for medical application.

    Science.gov (United States)

    Ma, Zheng; Li, Mei; Liu, Rui; Ren, Ling; Zhang, Yu; Pan, Haobo; Zhao, Ying; Yang, Ke

    2016-05-01

    Health of human beings is subjected to severe threats from the spread of harmful bacteria and the implant-associated infection remains a serious problem in clinic. In this study, a copper-bearing antibacterial titanium alloy, Ti-5Cu, has been developed for dental and orthopedic implant applications. The microstructure, mechanical property, electrochemical corrosion behavior, in vitro antibacterial performance, cytocompatibility and hemocompatibility of the alloy are systematically investigated. The results reveal that the Ti-5Cu alloy which consists of α-phase matrix and intermetallic compound Ti2Cu not only possesses strong antibacterial activity against both E. coli and S. aureus, but also exhibits better mechanical properties than the commercial pure titanium. It is confirmed that the release of trace amount of Cu ions from the alloy plays an important role in killing bacteria. In spite of the ion release, Ti-5Cu alloy still reveals excellent corrosion resistance. Moreover, good cytocompatibility and superior hemocompatibility make Ti-5Cu alloy to be a potential solution that could prevent the peri-implant infection in dental and orthopaedic applications. PMID:26975748

  20. Defects and Electron Densities in TiAl-based Alloys Containing Mn and Cu Studied by Positron Annihilation

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The defects and electron densities in Ti50Al50, Ti50Al48Mn2 and Ti50Al48Cu2 alloys have been studied by positron lifetime measurements. The results show that the free electron density in the bulk of binary TiAl alloy is lower than that of pure Ti or Al metal. The open volume of defects on the grain boundaries of binary TiAl alloy is larger than that of a monovacancy of Al metal. The additions of Mn and Cu into Ti-rich TiAl alloy will increase the free electron densities in the bulk and the grain boundary simultaneously, since one Mn atom or Cu atom which occupies the Al atom site provides more free electrons participating metallic bonds than those provided by an Al atom. It is also found the free electron density in the grain boundary of Ti50Al48Cu2 is higher than that of Ti50Al48Mn2 alloy, while the free electron density in the bulk of Ti50Al48Cu2 is lower than that of Ti50Al48Mn2 alloy. The behaviors of Mn and Cu atoms in TiAl alloy have been discussed.

  1. Conducting mechanisms of forming-free TiW/Cu{sub 2}O/Cu memristive devices

    Energy Technology Data Exchange (ETDEWEB)

    Yan, P.; Li, Y.; Hui, Y. J.; Zhong, S. J.; Zhou, Y. X.; Xu, L.; Liu, N.; Qian, H.; Sun, H. J., E-mail: shj@mail.hust.edu.cn; Miao, X. S. [Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology (HUST), Wuhan 430074 (China); School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2015-08-24

    P-type Cu{sub 2}O is a promising CMOS-compatible candidate to fabricate memristive devices for next-generation memory, logic and neuromorphic computing. In this letter, the microscopic switching and conducting mechanisms in TiW/Cu{sub 2}O/Cu memristive devices have been thoroughly investigated. The bipolar resistive switching behaviors without an electro-forming process are ascribed to the formation and rupture of the conducting filaments composed of copper vacancies. In the low resistive state, the transport of electrons in the filaments follows Mott's variable range hopping theory. When the devices switch back to high resistive state, the coexistence of Schottky emission at the Cu/Cu{sub 2}O interface and electron hopping between the residual filaments is found to dominate the conducting process. Our results will contribute to the further understanding and optimization of p-type memristive materials.

  2. Enthalpy of mixing of Cu-Ni-Ti liquid alloys at 1873 K

    International Nuclear Information System (INIS)

    The enthalpy of Cu-Ni-Ti ternary melt formation at 1873 K is investigated for sections with constant ratios of xNi:xCu = 1:3; 1:1 and 3:1 within a range of alloys with xTi = 0-0.6. A description is given to isothermal curves of enthalpy of mixing of liquid alloys for binary and ternary systems. It is revealed that the contribution from ternary interaction to the heat of alloy formation in a concentration range of xTi < 0.45 is exothermic, and in the other part of a concentration triangle is endothermic. The fact that the first partial enthalpies of mixing of Al, Sn, Y, Zr, Hf, Fe with Cu-Ni-Ti melts are exothermic values is testimony to the growth of liquid phase thermodynamic stability on dissolution of the metal additions

  3. Effect of surface treatments on the surface morphology, corrosion property, and antibacterial property of Ti-10Cu sintered alloy.

    Science.gov (United States)

    Zhang, Erlin; Liu, Cong

    2015-08-01

    Ti-10Cu sintered alloy has shown strong antibacterial properties against S. aureus and E. coli and good cell biocompatibility in vitro and in vivo, displaying potential application as an implant material. Surface treatments are always applied to implants to improve the surface biocompatibility. In this paper, several typically used surface treatments, including sandblasting (SB), sandblasted and large-grits acid etching (SLA), and alkaline heat treatment (AH) were chosen to modify the Ti-10Cu. A cp-Ti (commercially pure titanium) sample was used as control sample. The effect of surface treatments on the corrosion properties and antibacterial properties of the Ti-10Cu sintered alloy was investigated. After SB and SLA treatments, a rough surface with a TiO2 layer was formed on the surface, which reduced the corrosion resistance and enhanced the Ti and Cu ion release. After AH treatment, a smooth but microporous surface with a TiO2/titanate layer was formed, which improved slightly the corrosion resistance. However, the Cu ion and Ti ion release from the Ti-10Cu sample was promoted by AH treatment due to the fact that more Ti2Cu phases were exposed on the AH-treated Ti-10Cu sample. It was demonstrated that the Ti-10Cu samples after surface treatments still exhibited good antibacterial properties against S. aureus, which indicated that the surface treatment did not reduce the antibacterial activity. The control mechanism was thought to be related to the high Cu ion release even after surface treatments. It was expected that the surface treatments provided Ti-10Cu sintered alloy with good surface bioactivity without reduction in antibacterial activity. PMID:26201969

  4. Processing and microstructural development of Ag-clad Bi-Sr-Ca-Cu-O tapes

    International Nuclear Information System (INIS)

    Ag-clad Bi2Sr2CaCu2Ox (2212) and (Bi,Pb)2Sr2Ca2Cu3Ox (2223) tapes were fabricated by drawing and rolling. Highly textured microstructures and high critical current density values were obtained for each system. However, the heat treatments and phase evolutions for 2212 and 2223 were different. For 2212, nearly phase-pure powder was used, and the heat treatments consisted of partial melting followed by solid-state sintering. For 2223, several compositions, initial phases, and sintering schedules were used. Results are discussed in terms of microstructural evolution as observed by X-ray diffraction and scanning and transmission electron microscopy

  5. The crystallization of (NiCu)ZrTiAlSi glass/crystalline composite

    International Nuclear Information System (INIS)

    Alloys of composition (Ni1-xCux)60Zr18Ti13A15Si4 were investigated in the form of ribbons and massive samples. The microstructure of the massive samples consists of dendritic crystals in the amorphous or nanocrystalline matrix. The amount of the amorphous phase is the lowest in the sample with the highest Cu content. The segregation in the liquid phase, leading to the local differences in density and the composition of the crystallizing dendrites in the samples crystallized in the copper mould was shown. The typical compositions of the multi-component crystals could be distinguished; one with the increased content of aluminum, the second with the high content of silicon and third, with the high content of (NiCu) and (ZrTi). The cubic phase Ni(Cu)Ti(Zr) with Cu and Zr dissolved could be identified. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  6. Oxidation behavior of Cu nanoparticles embedded into semiconductive TiO{sub 2} matrix

    Energy Technology Data Exchange (ETDEWEB)

    Stranak, Vitezslav, E-mail: stranak@prf.jcu.cz [University of South Bohemia, Faculty of Science, Branisovska 31, 37005 Ceske Budejovice (Czech Republic); Drache, Steffen; Wulff, Harm [University of Greifswald, Institute of Physics, Felix-Hausdorff-Str. 6, 17489 Greifswald (Germany); Hubicka, Zdenek [Institute of Physics, Academy of Science of the Czech Republic, Na Slovance 2, 18221 Prague (Czech Republic); Tichy, Milan [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague (Czech Republic); Kruth, Angela [Leibniz Institute for Plasma Science and Technology, INP Greifswald e.V., Felix-Hausdorff-Straße 2, 17489 Greifswald (Germany); Helm, Christiane A.; Hippler, Rainer [University of Greifswald, Institute of Physics, Felix-Hausdorff-Str. 6, 17489 Greifswald (Germany)

    2015-08-31

    Metal nanoparticles embedded into a semiconductive matrix represent a promising material for widely sought advanced technological applications. We focused our interest on the preparation of TiO{sub 2} matrix with embedded Cu nanoparticles. In particular, we studied the effect of reactive discharge (Ar/O{sub 2}) exposition on copper oxidation, which can result in two stable forms: cuprous oxide (Cu{sub 2}O) and cupric oxide (CuO). Copper nanoparticles, of size in range 10–50 nm, were produced by magnetron sputtering in combination with gas aggregation. The beam of Cu nanoparticles was impinging onto a silicon substrate which was directly exposed to a reactive Ar/O{sub 2} magnetron discharge providing sputtering of Ti target at the same time. The properties of deposited nanocomposite Cu({sub x}O)–TiO{sub 2} were investigated by X-ray photoelectron spectroscopy, grazing incidence X-ray diffractometry, X-ray reflectometry and scanning electron microscopy techniques to reveal the nanocomposite properties and to understand the oxidation process of embedded Cu nanoparticles. It was found that CuO is preferentially formed if copper is exposed to active oxygen species (O{sup +}, O{sup −}, O{sup ⁎} etc.) produced in the reactive magnetron discharge. On the other hand, Cu{sub 2}O was observed in the case of copper reaction in ambient Ar/O{sub 2} atmosphere. As a result, two possible copper oxidation mechanisms are proposed, employing chemical kinetics. - Highlights: • Cu–TiO{sub 2} nanocomposite was prepared by plasma assisted methods. • Embedded Cu always occurs in oxidized phase depending on the way of oxidation. • CuO is formed if copper is exposed to active oxygen species produced in Ar/O{sub 2} discharge. • Cu{sub 2}O appears in the case of copper reaction in an ambient oxygen-based atmosphere. • Two possible copper oxidation mechanisms are proposed.

  7. Oxidation behavior of Cu nanoparticles embedded into semiconductive TiO2 matrix

    International Nuclear Information System (INIS)

    Metal nanoparticles embedded into a semiconductive matrix represent a promising material for widely sought advanced technological applications. We focused our interest on the preparation of TiO2 matrix with embedded Cu nanoparticles. In particular, we studied the effect of reactive discharge (Ar/O2) exposition on copper oxidation, which can result in two stable forms: cuprous oxide (Cu2O) and cupric oxide (CuO). Copper nanoparticles, of size in range 10–50 nm, were produced by magnetron sputtering in combination with gas aggregation. The beam of Cu nanoparticles was impinging onto a silicon substrate which was directly exposed to a reactive Ar/O2 magnetron discharge providing sputtering of Ti target at the same time. The properties of deposited nanocomposite Cu(xO)–TiO2 were investigated by X-ray photoelectron spectroscopy, grazing incidence X-ray diffractometry, X-ray reflectometry and scanning electron microscopy techniques to reveal the nanocomposite properties and to understand the oxidation process of embedded Cu nanoparticles. It was found that CuO is preferentially formed if copper is exposed to active oxygen species (O+, O−, O⁎ etc.) produced in the reactive magnetron discharge. On the other hand, Cu2O was observed in the case of copper reaction in ambient Ar/O2 atmosphere. As a result, two possible copper oxidation mechanisms are proposed, employing chemical kinetics. - Highlights: • Cu–TiO2 nanocomposite was prepared by plasma assisted methods. • Embedded Cu always occurs in oxidized phase depending on the way of oxidation. • CuO is formed if copper is exposed to active oxygen species produced in Ar/O2 discharge. • Cu2O appears in the case of copper reaction in an ambient oxygen-based atmosphere. • Two possible copper oxidation mechanisms are proposed

  8. Antimicrobial activity and biocompatibility of Ag{sup +}- and Cu{sup 2+}-doped biphasic hydroxyapatite/α-tricalcium phosphate obtained from hydrothermally synthesized Ag{sup +}- and Cu{sup 2+}-doped hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Radovanović, Željko, E-mail: zradovanovic@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade (Serbia); Jokić, Bojan; Veljović, Djordje; Dimitrijević, Suzana [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade (Serbia); Kojić, Vesna [Oncology Institute of Vojvodina, Institutski put 4, 21204 Sremska Kamenica (Serbia); Petrović, Rada; Janaćković, Djordje [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade (Serbia)

    2014-07-01

    Hydroxyapatite (HAp) powders doped with Ag{sup +} or Cu{sup 2+} were synthesized by a hydrothermal method in order to obtain biomaterial with an antimicrobial effect. The synthesis was performed with two contents of dopant (Ag{sup +} or Cu{sup 2+}) by considering both the antimicrobial activities and biocompatibility of the powders. The doped HAp was annealed at 1200 °C for 2 h with the intention of investigating the influence of doping with Ag{sup +} and Cu{sup 2+} on the creation of the biphasic HAp/α-tricalcium phosphate (HAp/α-TCP) and determining the antimicrobial activity and biocompatibility of the obtained biphasic powders. Analyses of all powders, undoped and doped HAp and HAp/α-TCP, were performed by Field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), atomic absorption spectroscopy (AAS) and energy-dispersive X-ray spectroscopy (EDS). The in vitro antibacterial activities of the powders were evaluated against: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. All powders showed good antimicrobial activity but generally the powders of doped HAp/α-TCP had more uniform results against all pathogenic microorganisms than the powders of doped HAp. In vitro biocompatibility tests, MTT and DET, were used to evaluate the biocompatibility of Ag{sup +}- and Cu{sup 2+}-doped HAp/α-TCP with MRC-5 human fibroblast cells. These tests confirmed that powders do not have a cytotoxic effect. The HAp/α-TCP powders doped with the lower content of Ag{sup +} and Cu{sup 2+} showed especially good biocompatibility. Antimicrobial and biocompatibility tests recommend the Ag{sup +}- and Cu{sup 2+}-doped HAp/α-TCP as promising material for use in reconstructive surgery of bone.

  9. Diffusion of Ag, Au and Cs implants in MAX phase Ti{sub 3}SiC{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Weilin, E-mail: weilin.jiang@pnnl.gov [Pacific Northwest National Laboratory, Richland, WA (United States); Henager, Charles H.; Varga, Tamas; Jung, Hee Joon; Overman, Nicole R. [Pacific Northwest National Laboratory, Richland, WA (United States); Zhang, Chonghong; Gou, Jie [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China)

    2015-07-15

    MAX phases (M: early transition metal; A: elements in group 13 or 14; X: C or N), such as titanium silicon carbide (Ti{sub 3}SiC{sub 2}), have a unique combination of both metallic and ceramic properties, which make them attractive for potential nuclear applications. Ti{sub 3}SiC{sub 2} has been considered as a possible fuel cladding material. This study reports on the diffusivities of fission product surrogates (Ag and Cs) and a noble metal Au (with diffusion behavior similar to Ag) in this ternary compound at elevated temperatures, as well as in dual-phase nanocomposite of Ti{sub 3}SiC{sub 2}/3C-SiC and polycrystalline CVD 3C-SiC for behavior comparisons. Samples were implanted with Ag, Au or Cs ions and characterized with various methods, including X-ray diffraction, electron backscatter diffraction, energy dispersive X-ray spectroscopy, Rutherford backscattering spectrometry, helium ion microscopy, and transmission electron microscopy. The results show that in contrast to immobile Ag in 3C-SiC, there is a significant outward diffusion of Ag in Ti{sub 3}SiC{sub 2} within the dual-phase nanocomposite during Ag ion implantation at 873 K. Similar behavior of Au in polycrystalline Ti{sub 3}SiC{sub 2} was also observed. Cs out-diffusion and release from Ti{sub 3}SiC{sub 2} occurred during post-implantation thermal annealing at 973 K. This study suggests caution and further studies in consideration of Ti{sub 3}SiC{sub 2} as a fuel cladding material for advanced nuclear reactors operating at very high temperatures.

  10. Ag@AgCl修饰TiO2-xCx光催化剂的制备及其可见光降解污染物性能%Preparation of a Ag@AgCl-Modified TiO2-xCx Photocatalyst and Its Performance for Degradation of Pollutants under Visible Light

    Institute of Scientific and Technical Information of China (English)

    聂龙辉; 胡瑶; 张旺喜

    2012-01-01

    C-doped TiO2 was prepared from butyl titanate and glucose by a hydrothermal method. The prepared C-doped TiO2 was further modified with Ag@AgCI. The obtained samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), BET surface area analysis, and UV-Vis diffuse reflectance spectroscopy. The photocatalytic activity of the samples was evaluated by the degradation of methyl orange and phenol under the visible light irradiation (λ >420 nm). After modification with Ag@AgCI, the C-doped TiO2 samples had a larger particle size and smaller surface area with enhanced response to visible light and greatly improved visible-light photocatalytic activity. The degradation rates of methyl orange and phenol over Ag@AgCI/TiO2-xCx were 5.5 and 3.4 times as large as those over TiO2-xCx, respectively. The photocatalytic activity of Ag@AgCI/TiCv2-xC, under visible light remained almost unchanged after three cycles.%以钛酸丁酯和葡萄糖为原料用水热法制备了碳掺杂二氧化钛,再进一步对其进行Ag@AgCl表面修饰.用X射线衍射(XRD),X射线光电子能谱(XPS),透射电镜(TEM),BET比表面仪和紫外-可见(UV-Vis)漫反射光谱等手段对样品进行测试表征;在可见光辐射下(λ>420 nm),以甲基橙和苯酚溶液的光催化降解实验来评价样品的活性.结果表明:经Ag@AgCl修饰后,样品的粒径增大,比表面积减小,对可见光的响应增强;可见光光催化效率有大幅度提高,对甲基橙和苯酚的降解效率分别是修饰前的5.5和3.4倍,且光催化剂经三次循环使用后活性基本保持不变.

  11. Electronic structure and x-ray magnetic circular dichroism in YbAgCu4 and YbInCu4

    Energy Technology Data Exchange (ETDEWEB)

    Antonov, VN; Bekenov, LV; Antropov, VP

    2014-04-08

    X-ray absorption and magnetic circular dichroism spectra at the L-3 edge of Yb have been studied theoretically in the mixed-valent compounds YbAgCu4 and YbInCu4 using the fully relativistic Dirac linear muffin-tin orbital band structure method. The effect of the spin-orbit (SO) interaction and Coulomb repulsion U on the electronic structure of YbAgCu4 and YbInCu4 is examined in the frame of the local spin-density approximation (LSDA)+SO+U method. The core-hole effect in the final states as well as the effect of the electric quadrupole E-2 and magnetic dipole M-1 transitions have been investigated. The calculated results are compared with available experimental data.

  12. Electronic structure and x-ray magnetic circular dichroism in YbAgCu4 and YbInCu4

    Energy Technology Data Exchange (ETDEWEB)

    Antonov, V N; Bekenov, L V; Antropov, V P

    2014-04-01

    X-ray absorption and magnetic circular dichroism spectra at the L3 edge of Yb have been studied theoretically in the mixed-valent compounds YbAgCu4 and YbInCu4 using the fully relativistic Dirac linear muffin-tin orbital band structure method. The effect of the spin-orbit (SO) interaction and Coulomb repulsion U on the electronic structure of YbAgCu4 and YbInCu4 is examined in the frame of the local spin-density approximation (LSDA)+SO+U method. The core-hole effect in the final states as well as the effect of the electric quadrupole E2 and magnetic dipole M1 transitions have been investigated. The calculated results are compared with available experimental data.

  13. Epitaxial Cu(001) films grown on a Cr/Ag/Fe/GaAs(001) buffer system

    International Nuclear Information System (INIS)

    We present a procedure to prepare single-crystalline, high-purity Cu(001) films (templates) suitable as substrates for subsequent epitaxial thin-film growth. The template films were grown in a dedicated molecular-beam epitaxy system on a Cr/Ag/Fe/GaAs(001) buffer layer system. Low-energy electron diffraction and X-ray diffraction were applied to determine the surface orientation and the epitaxial relationship between all layers of the stack. Post-annealing at moderate temperatures enhances the quality of the film as shown by low-energy electron diffraction and atomic force microscopy. X-ray photoemission and Auger electron spectroscopy confirm that no atoms of the buffer layers diffuse into the Cu film during the initial preparation and the post-annealing treatment. The completed Cu(001) template system can be exposed to air and afterwards refurbished by Ar+-ion bombardment and annealing, enabling the transfer between vacuum systems. The procedure provides suitable conductive thin film templates for studies of epitaxial thin films, e.g. on the magnetic and magnetotransport properties of Co and Ni based films and multilayers. - Highlights: • Preparation of epitaxial Cu(001) template films on an insulating substrate • Characterization of template structure, orientation, cleanness, and roughness • Template films can be exposed to air and refurbished in different vacuum system. • Template films are suitable for further thin film growth at up to 570 K

  14. Cu-TiB metal matrix composites prepared by powder metallurgy route

    Directory of Open Access Journals (Sweden)

    Guo Z.

    2015-01-01

    Full Text Available Titanium boride (TiB is characterized by good conductivity, high strength and high melting point. In this work, TiB was used to make Cu-TiB metal matrix composites (MMCs. Amounts of TiB added into Cu matrix were 2wt.%, 5wt.%, 10 wt.% and 15 wt.%. The samples were pressed at pressures of 500MPa, 600MPa, 700MPa and 800MPa and sintered at 820o and 920o, respectively. The properties of the sintered composites such as hardness and impact toughness were studied. Hardness and impact toughness of samples increased with increasing pressures and decreased with increasing contents of TiB. Composite with good mechanical properties and high conductivity was obtained from the sample containing 2wt.%TiB compacted at 800MPa and sintered at 920o. It was shown that 2wt.% TiB is a suitable content to make Cu-TiB MMCs with good mechanical properties and excellent conductivity.

  15. Anti-biofilm efficacy of low temperature processed AgCl–TiO{sub 2} nanocomposite coating

    Energy Technology Data Exchange (ETDEWEB)

    Naik, Kshipra, E-mail: kshipra_naik21@yahoo.co.in; Kowshik, Meenal, E-mail: meenal@goa.bits-pilani.ac.in

    2014-01-01

    Biofilms are a major concern in the medical settings and food industries due to their high tolerance to antibiotics, biocides and mechanical stress. Currently, the development of novel methods to control biofilm formation is being actively pursued. In the present study, sol–gel coatings of AgCl–TiO{sub 2} nanoparticles are presented as potential anti-biofilm agents, wherein TiO{sub 2} acts as a good supporting matrix to prevent aggregation of silver and facilitates its controlled release. Low-temperature processed AgCl–TiO{sub 2} nanocomposite coatings inhibit biofilm formation by Escherichia coli, Staphylococcus epidermidis and Pseudomonas aeruginosa. In vitro biofilm assay experiments demonstrated that AgCl–TiO{sub 2} nanocomposite coated surfaces, inhibited the development of biofilms over a period of 10 days as confirmed by scanning electron microscopy. The silver release kinetics exhibited an initial high release, followed by a slow and sustained release. The anti-biofilm efficacy of the coatings could be attributed to the release of silver, which prevents the initial bacterial adhesion required for biofilm formation. - Highlights: • Potential of AgCl–TiO{sub 2} nanocomposite coating to inhibit biofilm formation is exhibited. • Initial rapid release followed by later slow and sustained release of silver obtained. • TiO{sub 2} being porous and inorganic in nature acts as a good supporting matrix.

  16. The effect of nanoparticles size on photocatalytic and antimicrobial properties of Ag-Pt/TiO2 photocatalysts

    Science.gov (United States)

    Zielińska-Jurek, Anna; Wei, Zhishun; Wysocka, Izabela; Szweda, Piotr; Kowalska, Ewa

    2015-10-01

    Ag-Pt-modified TiO2 nanocomposites were synthesized using the sol-gel method. Bimetallic modified TiO2 nanoparticles exhibited improved photocatalytic activity under visible-light irradiation, better than monometallic Ag/TiO2 and Pt/TiO2 nanoparticles (NPs). All modified powders showed localized surface plasmon resonance (LSPR) in visible region. The photocatalysts' characteristics by X-ray diffractometry (XRD), scanning transmission electron microscopy (STEM), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption (BET method for specific surface area) showed that sample with the highest photocatalytic activity had anatase structure, about 93 m2/g specific surface area, maximum plasmon absorption at ca. 420 nm and contained small NPs of silver of 6 nm and very fine platinum NPs of 3 nm. The photocatalytic activity was estimated by measuring the decomposition rate of phenol in 0.2 mM aqueous solution under Vis and UV/vis light irradiation. It was found that size of platinum was decisive for the photocatalytic activity under visible light irradiation, i.e., the smaller Pt NPs were, the higher was photocatalytic activity. While, antimicrobial activities, estimated for bacteria Escherichia coli and Staphylococcus aureus, and pathogenic fungi belonging to Candida family, were only observed for photocatalysts containing silver, i.e., Ag/TiO2 and Ag-Pt/TiO2 nanocomposites.

  17. Mechanism of high dielectric performance of polymer composites induced by BaTiO3-supporting Ag hybrid fillers

    Science.gov (United States)

    Fang, Fang; Yang, Wenhu; Yu, Shuhui; Luo, Suibin; Sun, Rong

    2014-03-01

    BaTiO3-supporting Ag hybrid particles (BT-Ag) with varied fraction of Ag were synthesized by reducing silver nitrate in the glycol solution containing BaTiO3 (BT) suspensions. The Ag nano particles with a size of about 20 nm were discretely grown on the surface of the BT. The dielectric performance of the composites containing the BT-Ag as fillers in the matrix of polyvinylidene fluoride (PVDF) was investigated. The relative permittivity (ɛr) of the BT-Ag/PVDF composites increased prominently with the increase of BT-Ag loading amount, and the typical conductive path of the conductor/polymer system was not observed even with a high loading of BT-Ag. The ɛr at 100 Hz for the three BT-(0.31, 0.49, 0.61)Ag/PVDF composites at room temperature were 283, 350, and 783, respectively. The ɛr of the composites was enhanced by more than 3 times compared with that of the composite containing untreated BT nanoparticles at frequencies over 1 kHz and the loss tangent (tan δ) was less than 0.1 which should be attributed to the low conductivity of the composites. Theoretical calculations based on the effective medium percolation theory model and series-parallel model suggested that the enhanced permittivity of BT-Ag/PVDF composites should arise from the ultrahigh permittivity of BT-Ag fillers, which was over 104 and associated with the content of Ag deposited on the surface of BT.

  18. Inhibitory effect of super-hydrophobicity on silver release and antibacterial properties of super-hydrophobic Ag/TiO2 nanotubes.

    Science.gov (United States)

    Zhang, Licheng; Zhang, Lihai; Yang, Yun; Zhang, Wei; Lv, Houchen; Yang, Fei; Lin, Changjian; Tang, Peifu

    2016-07-01

    The antibacterial properties of super-hydrophobic silver (Ag) on implant surface have not yet to be fully illuminated. In our study, we investigate the protective effects of super-hydrophobic coating of silver/titanium dioxide (Ag/TiO2 ) nanotubes against bacterial pathogens, as well as its pattern of Ag release. Ag/TiO2 nanotubes are prepared by a combination of electrochemical anodization and pulse electrodeposition. The super-hydrophobic coating is prepared by modifying the surface of Ag/TiO2 nanotubes with 1H, 1H, 2H, 2H-perfluorooctyl-triethoxysilane (PTES). Surface features and Ag release are examined by SEM, X-ray photoelectron spectroscopy, contact-angle measurement, and inductively coupled plasma-mass spectrometry (ICP-MS). The antibacterial activity of super-hydrophobic coating Ag/TiO2 nanotubes is investigated both in vitro and in vivo. Consequently, the super-hydrophobic coating on Ag/TiO2 nanotubes shows a regularly arranged structure; and nano-Ag particles (10-30 nm) are evenly distributed on the surface or inside the nanotubes. The contact angles of water on the super-hydrophobic coating Ag/TiO2 nanotubes are all above 150°. In addition, the super-hydrophobic character displays a certain conserved effect that contributes to the sustained release of Ag. The super-hydrophobic Ag/TiO2 nanotubes are also effective in inhibiting bacterial adhesion, killing the adhering bacteria and preventing postoperative infection in rabbits. Therefore, it is expected that the super-hydrophobic Ag/TiO2 nanotubes which can contain the release of Ag, leading to stable release, may show a consistent surface antibacterial capability. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1004-1012, 2016. PMID:25995046

  19. Mechanical, structural and thermal properties of Ag-Cu and ZnO reinforced polylactide nanocomposite films.

    Science.gov (United States)

    Ahmed, Jasim; Arfat, Yasir Ali; Castro-Aguirre, Edgar; Auras, Rafael

    2016-05-01

    Plasticized polylactic acid (PLA) based nanocomposite films were prepared by incorporating polyethylene glycol (PEG) and two selected nanoparticles (NPs) [silver-copper (Ag-Cu) alloy (<100nm) and zinc oxide (ZnO) (<50 and <100nm)] through solvent casting method. Incorporation of Ag-Cu alloy into the PLA/PEG matrix increased the glass transition temperature (Tg) significantly. The crystallinity of the nanocomposites (NCs) was significantly influenced by NP incorporation as evidenced from differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis. The PLA nanocomposite reinforced with NPs exhibited much higher tensile strength than that of PLA/PEG blend. Melt rheology of NCs exhibited a shear-thinning behavior. The mechanical property drastically reduced with a loading of NPs, which is associated with degradation of PLA. SEM micrographs exhibited that both Ag-Cu alloy and ZnO NPs were dispersed well in the PLA film matrix. PMID:26893045

  20. Electron configuration and charge state of electrically active Cu, Ag and Au ions in ZnSe

    Science.gov (United States)

    Nedeoglo, N. D.; Sirkeli, V. P.; Nedeoglo, D. D.; Laiho, R.; Lähderanta, E.

    2006-08-01

    The Hall effect, electrical conductivity and electron mobility are investigated at temperatures between 55 and 500 K in n-ZnSe crystals doped with Cu, Ag or Au. The presence of a small amount of Cu atoms leads to an inversion of the sign of the Hall coefficient at temperatures above 300 K. Anomalous temperature dependence of the electron mobility is observed in the samples with low Cu concentration (AgZn+ and AuZn+ with d10 electron configuration forming single energy levels near the valence band. Au atoms form mainly interstitial Aui donors at low doping concentrations and substitutional AuZn and AuZn-based acceptors at high doping concentrations. Time stimulation of the amphoteric properties of Ag is discussed.

  1. CuO and Ag2O/CuO Catalyzed Oxidation of Aldehydes to the Corresponding Carboxylic Acids by Molecular Oxygen

    OpenAIRE

    Yaowu Sha; Daxin Shi; Qingyong Tian

    2008-01-01

    Furfural was oxidized to furoic acid by molecular oxygen under catalysis by 150nm-sized Ag2O/CuO (92%) or simply CuO (86.6%). When 30 nm-size catalyst was used,the main product was a furfural Diels-Alder adduct. Detailed reaction conditions andregeneration of catalysts were investigated. Under optimal conditions, a series of aromaticand aliphatic aldehydes were oxidized to the corresponding acids in good yields.

  2. CuO and Ag2O/CuO Catalyzed Oxidation of Aldehydes to the Corresponding Carboxylic Acids by Molecular Oxygen

    Directory of Open Access Journals (Sweden)

    Yaowu Sha

    2008-04-01

    Full Text Available Furfural was oxidized to furoic acid by molecular oxygen under catalysis by 150nm-sized Ag2O/CuO (92% or simply CuO (86.6%. When 30 nm-size catalyst was used,the main product was a furfural Diels-Alder adduct. Detailed reaction conditions andregeneration of catalysts were investigated. Under optimal conditions, a series of aromaticand aliphatic aldehydes were oxidized to the corresponding acids in good yields.

  3. Ag2S/CdS/TiO2 Nanotube Array Films with High Photocurrent Density by Spotting Sample Method.

    Science.gov (United States)

    Sun, Hong; Zhao, Peini; Zhang, Fanjun; Liu, Yuliang; Hao, Jingcheng

    2015-12-01

    Ag2S/CdS/TiO2 hybrid nanotube array films (Ag2S/CdS/TNTs) were prepared by selectively depositing a narrow-gap semiconductor-Ag2S (0.9 eV) quantum dots (QDs)-in the local domain of the CdS/TiO2 nanotube array films by spotting sample method (SSM). The improvement of sunlight absorption ability and photocurrent density of titanium dioxide (TiO2) nanotube array films (TNTs) which were obtained by anodic oxidation method was realized because of modifying semiconductor QDs. The CdS/TNTs, Ag2S/TNTs, and Ag2S/CdS/TNTs fabricated by uniformly depositing the QDs into the TNTs via the successive ionic layer adsorption and reaction (SILAR) method were synthesized, respectively. The X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectrum (XPS) results demonstrated that the Ag2S/CdS/TNTs prepared by SSM and other films were successfully prepared. In comparison with the four films of TNTs, CdS/TNTs, Ag2S/TNTs, and Ag2S/CdS/TNTs by SILAR, the Ag2S/CdS/TNTs prepared by SSM showed much better absorption capability and the highest photocurrent density in UV-vis range (320~800 nm). The cycles of local deposition have great influence on their photoelectric properties. The photocurrent density of Ag2S/CdS/TNTs by SSM with optimum deposition cycles of 6 was about 37 times that of TNTs without modification, demonstrating their great prospective applications in solar energy utilization fields. PMID:26428017

  4. Effects of Carrier on CuO/TiO2 and CuO/Ti0.5Zr0.5O2 Catalysts in the NO+CO Reaction

    Institute of Scientific and Technical Information of China (English)

    Guang Hui DING; Xiao Yuan JIANG; Xiao Ming ZHENG

    2005-01-01

    Using TiO2 and Ti0.5Zr0.5O2 as carriers, the CuO/TiO2 and CuO/Ti0.5Zr0.5O2 catalysts were prepared by the impregnation method with Gu(NO3)2 as active component. The catalytic activities in NO+CO reaction were investigated using a microreactor-GC system, and structure and reducibility of catalysts were characterized by means of physical adsorption, TPR, XRD, NO-TPD technologies. It was found that the activity of CuO/Ti0.5Zr0.5O2 catalyst was higher than that of CuO/TiO2, probably due to the large specific surface area of Ti0.5Zr0.5O2 that played an important role in NO+CO reaction.

  5. The Controlled Single-Step Synthesis of Ag/TiO2 and Au/TiO2 by Ultrasonic Spray Pyrolysis (USP)

    Science.gov (United States)

    Bogovic, J.; Rudolf, R.; Friedrich, B.

    2016-01-01

    This article reports the synthesis of Ag/TiO2 and Au/TiO2 nanoparticles by single-step ultrasonic spray pyrolysis (USP) conducted by an investigation of the process parameters and the morphological characteristics of the obtained nanostructures. The influence of the ratio in the precursor solution, physical characteristics of used components, and temperature had a large influence on the formation of different nanoparticle morphologies. The experimental investigations were performed using classic USP equipment, with variations of the process parameters. Scanning electron microscopy, transmission electron microscopy, and focused ion beam analyses were used to characterize the complex nanostructures. Based on the obtained results, the optimal process window for the formation of the different morphologies for the Ag/TiO2 and Au/TiO2 nanoparticles is determined and the possibility of synthesis of the core-shell structures in one step by USP is confirmed.

  6. Brazing of zirconia to titanium using Ag-Cu and Au-Ni filler alloys

    Directory of Open Access Journals (Sweden)

    Jean S. Pimenta

    2013-12-01

    Full Text Available Advanced ceramic is usually joined to metal by the well-known direct brazing process, where costly active filler alloys can be considered a limitation. Brazing using active-metal-free filler alloy as insert between the joint components is an attempt to overcome it. The active metal diffusion from the titanium member through the bulk of molten filler to the ceramic was responsible to produce an active filler alloy in loco and promote reduction of the zirconium oxide to improve wetting on the ceramic surface. Unalloyed titanium was joined in a high-vacuum furnace (<3x10-5 mbar to yttria-tetragonal zirconia polycristals (Y-TZP and zirconia partially stabilized with magnesia (Mg-PSZ, where commercial fillers Ag-28Cu and Au-18Ni with respective thermal cycles were evaluated. Helium gas leak detection test was performed at the ceramic/metal interface at room temperature; samples from reliable vacuum tight joints were examined by microstructural analysis techniques and energy dispersive X-ray analysis at the joint cross-section. Tight joints were produced with eutectic Ag-Cu filler, revealing an intermetallic layer and a dark reaction layer near the ceramic surface; titanium diffusion was efficient for superficial chemical interactions between individual components. Brazing joints were also tested using three-point flexure testing.

  7. Adsorption of Ag, Cu and Hg from aqueous solutions using expanded perlite

    International Nuclear Information System (INIS)

    The aim of the present work was to investigate the ability of expanded perlite (EP) to remove of silver, copper and mercury ions from aqueous solutions. Batch adsorption experiments were carried out and the effect of pH, adsorbent dosage, contact time and temperature of solution on the removal process has been investigated. The optimum pH for the adsorption was found to be 6.5. Adsorption of these metal ions reached their equilibrium concentration in 120, 240 and 180 min for Ag (I), Cu (II) and Hg (II) ions, respectively. Experimental data were also evaluated in terms of kinetic characteristics of adsorption and it was found that adsorption process for these metal ions followed well pseudo-second-order kinetics. Using Langmuir isotherm model, maximum adsorption capacity of EP was found to be 8.46, 1.95 and 0.35 mg/g for Ag (I), Cu (II) and Hg (II) ions, respectively. Finally, the thermodynamic parameters including, the change of free energy (ΔGo), enthalpy (ΔHo) and entropy (ΔSo) of adsorption were calculated for each metal ion. The results showed that the adsorption of these metal ions on EP was feasible and exothermic at 20-50 deg. C.

  8. Electrochemical depositions of fluorohydroxyapatite doped by Cu2+, Zn2+, Ag+ on stainless steel substrates

    International Nuclear Information System (INIS)

    Fluoridated hydroxyapatite (FHA, Ca10(PO4)6(OH)2-xFx where 0 2+, Cu2+, Ag+) substituted fluoridated hydroxyapatite coatings (M-FHA) were deposited on the surface of medical grade 316L stainless steel samples by electrochemical deposition technique. The FHA coatings were co-substituted with antibacterial ions (Zn2+, Cu2+ or Ag+) by co-precipitation and ion-exchange methods. Characterization studies of coatings from X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDX) showed that the obtained layers are monophase crystals FHA and did not contain any discernible crystalline impurity. The particles of all samples are of nano size that gives thin layers. The surface morphology, microstructure and Ca/P atomic ratio of the FHA coatings can be regulated by varying electrolyte temperature. This later affects the porosity of the coating surface and the chemical compositions of the deposits. Quantitative elemental analysis indicates that the copper, zinc and silver ions are incorporated into the Fluorohydroxyapatite. The antimicrobial effects of doped fluorohydroxyapatite coatings against pathogen bacterial strains Staphylococcus aureus were tested in liquid media. The results are promising and demonstrated that all doped FHA samples exhibit excellent antimicrobial activity “in vitro” against the microorganism, so the antimicrobial properties of the coatings developed are improved.

  9. Hot Deformation Characteristics and Processing Maps of the Cu-Cr-Zr-Ag Alloy

    Science.gov (United States)

    Zhang, Yi; Chai, Zhe; Volinsky, Alex A.; Sun, Huili; Tian, Baohong; Liu, Ping; Liu, Yong

    2016-03-01

    The hot deformation behavior of the Cu-Cr-Zr-Ag alloy has been investigated by hot compressive tests in the 650-950 °C temperature and 0.001-10 s-1 strain rate ranges using Gleeble-1500D thermo-mechanical simulator. The microstructure evolution of the alloy during deformation was characterized using optical and transmission electron microscopy. The flow stress decreases with the deformation temperature and increases with the strain rate. The apparent activation energy for hot deformation of the alloy was 343.23 kJ/mol. The constitutive equation of the alloy based on the hyperbolic-sine equation was established to characterize the flow stress as a function of the strain rate and the deformation temperature. The processing maps were established based on the dynamic material model. The optimal processing parameters for hot deformation of the Cu-Cr-Zr-Ag alloy are 900-950 °C and 0.001-0.1 s-1 strain rate. The evolution of DRX microstructure strongly depends on the deformation temperature and the strain rate.

  10. Quantum fluctuation and vibrational dynamics of aqueous Cu+ and Ag+ clusters

    International Nuclear Information System (INIS)

    Highlights: • The structures and infrared spectra of Ag+(H2O)n (n = 1–4) and Cu+(H2O) are studied. • We applied “on-the-fly” ab initio MD, ab initio PIMD, and ab initio RPMD simulations. • The thermal and the nuclear quantum effects result in significant red shift. • The RPMD simulation improves the spectral peak positions substantially. • Unique scaling of harmonic frequencies fails to describe such anharmonic effects. - Abstract: The structures and infrared spectra of Ag+(H2O)n (n = 1–4) and Cu+(H2O) are studied by “on-the-fly” ab initio MD, ab initio PIMD, and ab initio RPMD simulations. It is found that the anharmonicity due to nuclear quantum and thermal effects acts differently depending on the system as well as the type of vibrational mode. In the low-frequency region, the spectra become a broad band as the cluster size increases due to the complex mode couplings, which is qualitatively different from the harmonic spectra. In contrast, the HOH bending modes are systematically red-shifted by a small amount due to the anharmonicity. The OH stretching modes are found to be also red-shifted, but the amount of shift is more dependent on the system. Consequently, these effects cannot be described by unique scaling of harmonic frequencies

  11. Ultrasonic properties of Cu45Zr(45-x)HfxAg10 glassy alloys

    International Nuclear Information System (INIS)

    Using ultrasonics, the acoustic characteristics of Cu45Zr(45-x)HfxAg10 (x=0-25) glassy alloys were examined in terms of complex elasticity. The values of bulk modulus (K), Lame parameter (λ), Young's (E) and shear (G) moduli of Cu45Zr(45-x)HfxAg10 glassy alloys are found to have a unique order for metallic materials, except for polymers. The large Poisson ratio (∝0.421) and the lower G /K ratio (∝0.167) at 25 at% Hf indicate rubbery characteristics that readily undergo uniaxial volume-preserving deformation but resist three-dimensional nonvolume-preserving deformation. The complex dynamic viscosity shows that visco-elasticity of the glassy alloys is dominated by shear motion. The large peaks in K and λ, and small ones in E and G at 5 at% Hf, and one large peak in the shear attenuation coefficient at 2.5 at% Hf, may indicate atomic morphological change by electron-transverse phonon coupling. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Effect of Cooling Rate on the Longitudinal Modulus of Cu3Sn Phase of Ag-Sn-Cu Amalgam Alloy (Part II

    Directory of Open Access Journals (Sweden)

    R. H. Rusli

    2015-10-01

    Full Text Available Effects of cooling rate (at the time of solidification on the elastic constants of Cu3Sn phase of Ag-Sn-Cu dental amalgam alloy were studied. In this study, three types of alloys were made, with the composition Cu-38-37 wt% Sn by means of casting, where each alloy was subjected to different cooling rate, such as cooling on the air (AC, air blown (AB, and quenched in the water (WQ. X-ray diffraction, metallography, and Scanning Electron Microscopy with Energy Dispersive Spectroscopy studies of three alloys indicated the existence of Cu3Sn phase. Determination of the modulus of elasticity of Cu3Sn (ε phase was carried out by the measurement of longitudinal and transversal waves velocity using ultrasonic technique. The result shows that Cu3Sn (ε phase on AC gives higher modulus of elasticity values than those of Cu3Sn (ε on AB and WQ. The high modulus of elasticity value will produce a strong Ag-Sn-Cu dental amalagam alloy.

  13. Mechanical Behavior of Sn-3.0Ag-0.5Cu/Cu Solder Joints After Isothermal Aging

    Science.gov (United States)

    Nguyen, Van Luong; Chung, Chin-Sung; Kim, Ho-Kyung

    2016-01-01

    The tensile impact behavior of lead-free Sn-3Ag-0.5Cu/Cu solder joints aged at 413 K and 453 K for times ranging from 24 h to 1000 h has been investigated in this study. The activation energy for growth of the intermetallic compound (IMC) layer was estimated and compared with literature values. Additionally, the tensile strength of solder joints with IMC thickness of 17.6 μm was found to be more sensitive to the strain rate as compared with solder joints with thinner IMC layers. Equations representing the relationships among the effective stress, strain rate, aging time, and aging temperature as well as IMC thickness were established using matrix laboratory (MATLAB) software. These equations show that the tensile strength decreases with increase in the IMC thickness to about 8 μm, after which it becomes nearly constant when the IMC thickness is between approximately 8 μm and 14 μm, before decreasing significantly when the IMC thickness exceeds 14 μm. The main reason for these characteristics was excessive increase in the IMC thickness of solder joints, causing a change in the stress concentration of the tensile load from the protruding region to the inside of the IMC layer at the same tested strain rate.

  14. Enhanced adsorption and visible-light-induced photocatalytic activity of hydroxyapatite modified Ag-TiO{sub 2} powders

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y.; Liu, C.Y. [School of Physics Science and Technology, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Wei, J.H., E-mail: jhwei@whu.edu.cn [School of Physics Science and Technology, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072 (China); Key Laboratory of Low Dimensional Materials and Application Technology, Xiangtan University, Ministry of Education, Hunan 411105 (China); Xiong, R.; Pan, C.X.; Shi, J. [School of Physics Science and Technology, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072 (China)

    2010-08-15

    In order to get a kind of materials with enhanced adsorption and photocatalytic performance, hydroxyapatite modified Ag-TiO{sub 2} powders (Ag-TiO{sub 2}-HAP) were prepared by a facile wet chemical strategy. The powders were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis absorption spectroscopy, N{sub 2} adsorption-desorption measurement (BET), photoluminescence spectroscopy (PL), etc. The photocatalytic activities were evaluated by photocatalytic oxidation decomposition of acetone in air under visible-light illumination. The results showed that the coupled system indicated a highest photocatalytic activity and photochemical stability under visible-light irradiation than all the other catalysts. The intensively improved visible-light-induced photocatalytic activity of the Ag-TiO{sub 2}-HAP hybrids could be attributed to its strong absorption in the visible-light region, low recombination rate of the electron-hole pair and large BET specific surface area.

  15. Enhanced adsorption and visible-light-induced photocatalytic activity of hydroxyapatite modified Ag-TiO2 powders

    International Nuclear Information System (INIS)

    In order to get a kind of materials with enhanced adsorption and photocatalytic performance, hydroxyapatite modified Ag-TiO2 powders (Ag-TiO2-HAP) were prepared by a facile wet chemical strategy. The powders were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis absorption spectroscopy, N2 adsorption-desorption measurement (BET), photoluminescence spectroscopy (PL), etc. The photocatalytic activities were evaluated by photocatalytic oxidation decomposition of acetone in air under visible-light illumination. The results showed that the coupled system indicated a highest photocatalytic activity and photochemical stability under visible-light irradiation than all the other catalysts. The intensively improved visible-light-induced photocatalytic activity of the Ag-TiO2-HAP hybrids could be attributed to its strong absorption in the visible-light region, low recombination rate of the electron-hole pair and large BET specific surface area.

  16. First-principles theory of short-range order in size-mismatched metal alloys: Cu-Au, Cu-Ag, and Ni-Au

    International Nuclear Information System (INIS)

    We describe a first-principles technique for calculating the short-range order (SRO) in disordered alloys, even in the presence of large anharmonic atomic relaxations. The technique is applied to several alloys possessing large size mismatch: Cu-Au, Cu-Ag, Ni-Au, and Cu-Pd. We find the following: (i) The calculated SRO in Cu-Au alloys peaks at (or near) the left-angle 100 right-angle point for all compositions studied, in agreement with diffuse scattering measurements. (ii) A fourfold splitting of the X-point SRO exists in both Cu0.75Au0.25 and Cu0.70Pd0.30, although qualitative differences in the calculated energetics for these two alloys demonstrate that the splitting in Cu0.70Pd0.30 may be accounted for by T=0 K energetics while T≠0 K configurational entropy is necessary to account for the splitting in Cu0.75Au0.25. Cu0.75Au0.25 shows a significant temperature dependence of the splitting, in agreement with recent in situ measurements, while the splitting in Cu0.70Pd0.30 is predicted to have a much smaller temperature dependence. (iii) Although no measurements exist, the SRO of Cu-Ag alloys is predicted to be of clustering type with peaks at the left-angle 000 right-angle point. Streaking of the SRO peaks in the left-angle 100 right-angle and left-angle 1 (1) /(2) 0 right-angle directions for Ag- and Cu-rich compositions, respectively, is correlated with the elastically soft directions for these compositions. (iv) Even though Ni-Au phase separates at low temperatures, the calculated SRO pattern in Ni0.4Au0.6, like the measured data, shows a peak along the left-angle ζ00 right-angle direction, away from the typical clustering-type left-angle 000 right-angle point. (v) The explicit effect of atomic relaxation on SRO is investigated and it is found that atomic relaxation can produce significant qualitative changes in the SRO pattern, changing the pattern from ordering to clustering type, as in the case of Cu-Ag. copyright 1998 The American Physical Society

  17. Novel PdAgCu ternary alloy as promising materials for hydrogen separation membranes: Synthesis and characterization

    Science.gov (United States)

    Tarditi, Ana M.; Cornaglia, Laura M.

    2011-01-01

    The use of the sequential electroless plating method allowed us to obtain the PdAgCu ternary alloy on top of dense stainless steel (SS) 316 L disks. The XRD analysis indicated that initially the nucleation of the two phases of the alloy (FCC and BCC) takes place, but the FCC/BCC ratio increases with the annealing time at 500 °C in H 2 stream. After 162 h, the film contained only the FCC phase, which presents promising properties to be applied in the synthesis of hydrogen selective membranes. SEM cross-section results showed that a dense, continuous, defect-free film was deposited on top of the SS support, and the EDS data indicated that no significant gradient was present on the thickness of the film. XPS and LEIS allowed us to determine that Cu and Ag surface segregation takes place after annealing up to 500 °C/5 days. In the top-most surface layer, Ag enrichment takes place as determined by ARXPS experiments which can be the result of the lower surface tension of Ag compared to that of Cu and Pd. Increasing the annealing temperature results in an increase of the Ag surface segregation while the Cu concentration in the top-most surface layer decreases.

  18. Changes in the real structure and magnetoresistance of Co90Fe10/Cu and Co90Fe10/Cu85Ag10Au5 multilayers after annealing

    International Nuclear Information System (INIS)

    Annealing of the (1.1 nm Co90Fe10/2.2 nm Cu)x20 and (1.1 nm Co90Fe10/2.2 nm Cu85Ag10Au5)x20 multilayers at 235 deg. C improved their magnetoresistance as compared to the virgin samples. Annealing at higher temperatures resulted in degradation of the magnetoresistance effect. This observation raised the motivation of a detailed structural study using small-angle X-ray scattering, wide-angle X-ray diffraction, electron diffraction and transmission electron microscopy with the aim to link the structural changes in the system to the changes in the magnetoresistance. The structure studies have shown that the maximum of the magnetoresistance observed after annealing at 235 deg. C is related to the separation of Co90Fe10 and Cu, which are partly intermixed at interfaces after the deposition process. The decay of the GMR effect at higher annealing temperatures is caused by an increase of the interface roughness, which led in the Co90Fe10/Cu multilayers to occurrence of non-continuous interfaces and to short-circuiting of magnetic layers. In the Cu85Ag10Au5 multilayers, the combination of small-angle X-ray scattering and wide-angle X-ray diffraction has shown that Cu85Ag10Au5 did not form an alloy with the nominal composition: Only a part of Au and Ag was dissolved in the copper structure; the remainder of Ag and Au formed precipitates

  19. Hardening by precipitation of the alloy Cu-2.3 Ti w%

    International Nuclear Information System (INIS)

    The precipitation process in an alloy of Cu-2.3 Ti w% was studied with differential scanning calorimetry (DSC). Analysis of the calorimetric curves shows the presence of two exothermic reactions (stages 1 and 2) and two endothermic effects (stages 3 and 4). The activation energies, calculated by the Kissinger method, turned out to be much lower than those for the diffusion of titanium in copper, due to the heavy contribution of the vacancies introduced by the quenching. The kinetic parameters were obtained by a convolution method based on the Mehl-Johnson-Avrami formula. The energetic, kinetic and molar heat of precipitation evaluations for the Cu4Ti particles were obtained using the van't Hoff isochor equations, showing that stage 1 corresponds to the formation of metastable particles of Cu4Ti and stage 2 to the cellular precipitation of the stable phase of Cu3Ti. Stages 3 and 4 would correspond to the dissolution of these particles. After submitting the material to different thermomechanical treatments, Vickers micro hardness measurements corroborated the presence of these precipitates in the matrix, with maximum hardness occurring when the material is aged at 560 K for 240 minutes. Cold deformation, before aging treatments, blocks the formation of Cu4Ti particles, and solute segregation occurs at the partial dislocations (CW)

  20. Effect of intermetallic compounds on the thermal conductivity of Ti-Cu composites

    International Nuclear Information System (INIS)

    Ti films were deposited by magnetron sputtering on polycrystalline Cu substrates. The samples were annealed at different temperatures and characterized by x-ray diffraction for phase identification, scanning electron microscopy, and energy dispersive spectrometry for microstructure and composition and transient thermoreflectance for thermal conductivity and interface thermal conductance. The results showed that the diffused layer of Ti in Cu contained intermetallic compounds and solid solution of Ti in Cu. The thermal conductivity of the diffused layer is reduced, and the thickness increased for higher annealing temperature. The interface thermal conductance also decreased for higher temperature of annealing. A stable Cu4Ti phase was formed after annealing at 725 °C with thermal conductivity of 10 W m−1 K−1. The interface thermal conductance between the intermetallic compound and the solid solution of Ti in Cu also was reduced to 30 MW m−2 K−1. The effective thermal resistance of the diffused layer and the interface was found to increase for higher annealing temperature

  1. Effect of intermetallic compounds on the thermal conductivity of Ti-Cu composites

    Energy Technology Data Exchange (ETDEWEB)

    Jagannadham, K., E-mail: jag-kasichainula@ncsu.edu [Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2016-03-15

    Ti films were deposited by magnetron sputtering on polycrystalline Cu substrates. The samples were annealed at different temperatures and characterized by x-ray diffraction for phase identification, scanning electron microscopy, and energy dispersive spectrometry for microstructure and composition and transient thermoreflectance for thermal conductivity and interface thermal conductance. The results showed that the diffused layer of Ti in Cu contained intermetallic compounds and solid solution of Ti in Cu. The thermal conductivity of the diffused layer is reduced, and the thickness increased for higher annealing temperature. The interface thermal conductance also decreased for higher temperature of annealing. A stable Cu{sub 4}Ti phase was formed after annealing at 725 °C with thermal conductivity of 10 W m{sup −1} K{sup −1}. The interface thermal conductance between the intermetallic compound and the solid solution of Ti in Cu also was reduced to 30 MW m{sup −2} K{sup −1}. The effective thermal resistance of the diffused layer and the interface was found to increase for higher annealing temperature.

  2. Ferroelectric and magnetic properties of Ho2CuTiO6 double perovskite

    International Nuclear Information System (INIS)

    Ho2CuTiO6 double pervoskite is synthesized by solid state reaction method and the phase formation was confirmed by X-ray diffraction. Ho2CuTiO6 crystallizes in space group P63 cm and are isostructural in AMnO3 structure. We have investigated the effect of the presence of a magnetic ion (Ho3+∼10.4μB) in Ho2CuTiO6, on the magnetic properties, compared to that of an isostructural double perovskite containing Y-ion (non-magnetic), i.e., Y2CuTiO6. Magnetization measurements on Ho2CuTiO6 showed paramagnetic moment of 0.026μB/Ho at room temperature in an applied field of 7 T although no saturation is observed at room temperature, whereas, at 5 K, the paramagnetic moment was 0.3μB/Ho in the same field. Since this compound is non-centrosymmetric, it is of interest to look into the possibility of realizing multiferroicity (coexistence of magnetic and ferroelectric properties) in these double perovskite systems, especially the Ho-containing compound, for possible applications

  3. Hydrogen generation by photoelectrochemical effect of the Cu-doped TiO2 photoanode

    International Nuclear Information System (INIS)

    TiO2 film photoanodes with a size of 1 × 1 cm2 were fabricated by a spin coating method. Cu-doped TiO2 powder with various Cu concentrations (0.2, 0.4, 0.6 and 0.8 at%) and surfactant were used as starting materials in coating Cu-doped TiO2 thin films onto FTO/glass substrate. Crystalline structure of TiO2 material, microstructure of the photoanode films and their thickness were identified by x-ray diffraction and Raman scattering. Hydrogen generation from water by photoelectrochemical effect in the visible light was observed by recording I/V characteristics of the photoanode in dark and light regimes. The obtained results have shown that the hydrogen generation efficiency of photoanode nonlinearly depends on Cu concentration. The nonlinear dependence of the hydrogen generation efficiency may be due to a change of resistivity of the film photoanode that is related with the random distribution of the hetero-junction between interfaces of TiO2 and CuO nanoparticles. (paper)

  4. Ti-Ni-Cu shape-memory alloy thin film formed on polyimide substrate

    International Nuclear Information System (INIS)

    Ti-Ni-Cu shape-memory alloy (SMA) thin films were sputter-deposited on heated polyimide substrates. Ti-Ni-Cu films deposited at substrate temperatures of 543 and 583 K were found to be crystalline. Especially, a Ti48Ni29Cu23 film deposited at 583 K exhibited a high martensitic transformation temperature above room temperature and a narrow transformation temperature range, which enable the film to be used at room temperature. Double-beam cantilevers made of 8 μm thick Ti48Ni29Cu23 films deposited on 12.5 and 25 μm thick polyimide substrates displayed a repeatable shape-memory effect by a battery of 1.5 V and it was verified that the composite film consisting of an 8 μm thick Ti48Ni29Cu23 film and a 25 μm thick polyimide film is capable of moving 0.18 g wings of a dragonfly toy up and down. These results offer the prospect for using an SMA/polyimide actuator as a convenient small actuator, which will find wide-ranging applications

  5. Micro-PIXE and channeling PIXE analysis of Ag-doped YBa2Cu3O7-δ thin films

    International Nuclear Information System (INIS)

    Nuclear Microscopy, utilizing a 2 MeV He+ beam for channeling Rutherford Backscattering (RBS) and PIXE analysis, was used to characterise Ag-doped YBa2Cu3O7-δ thin films and measure the lateral distribution of the Ag. The samples were prepared by in situ two-beam pulsed laser deposition in order to investigate the effects of such dopings on critical current densities . Films deposited at temperatures above 650 deg. C form needle-like surface structures with a length of up to 100 μm; these tend to align with in-plane a-b axis. Results for a sample prepared at a substrate temperature of 730 deg. C and a maximum Ag concentration of 5 at.% are discussed. The needle-like structures were found to be rich in Ag and Cu, and the YBa2Cu3O7-δ film contained 0.02 at.% Ag. Broad beam PIXE-channeling results indicate that 19% of the Ag is substitutional

  6. Microstructures and fatigue fracture behavior of an Al-Cu-Mg-Ag alloy with addition of rare earth Er

    International Nuclear Information System (INIS)

    The effects of rare earth erbium (Er) on microstructures and fatigue fracture behavior of an Al-Cu-Mg-Ag alloy were investigated. Microstructural examinations first revealed that the precipitation kinetics of Ω phase was distinctly retarded by promoting the formation of θ' phase with the Er addition during the initial aging. The fatigue crack propagation resistance of Er-containing microstructure was significantly enhanced arising from the presence of the crystallographic secondary cracks, which was directly relative to the large grain size. Results also suggested that the dendritic substructure of as-cast Al-Cu-Mg-Ag alloy was refined remarkably by Er addition.

  7. Antibacterial effect of copper-bearing titanium alloy (Ti-Cu) against Streptococcus mutans and Porphyromonas gingivalis

    Science.gov (United States)

    Liu, Rui; Memarzadeh, Kaveh; Chang, Bei; Zhang, Yumei; Ma, Zheng; Allaker, Robert P.; Ren, Ling; Yang, Ke

    2016-07-01

    Formation of bacterial biofilms on dental implant material surfaces (titanium) may lead to the development of peri-implant diseases influencing the long term success of dental implants. In this study, a novel Cu-bearing titanium alloy (Ti-Cu) was designed and fabricated in order to efficiently kill bacteria and discourage formation of biofilms, and then inhibit bacterial infection and prevent implant failure, in comparison with pure Ti. Results from biofilm based gene expression studies, biofilm growth observation, bacterial viability measurements and morphological examination of bacteria, revealed antimicrobial/antibiofilm activities of Ti-Cu alloy against the oral specific bacterial species, Streptococcus mutans and Porphyromonas gingivalis. Proliferation and adhesion assays with mesenchymal stem cells, and measurement of the mean daily amount of Cu ion release demonstrated Ti-Cu alloy to be biocompatible. In conclusion, Ti-Cu alloy is a promising dental implant material with antimicrobial/antibiofilm activities and acceptable biocompatibility.

  8. Photocatalytic properties and selective antimicrobial activity of TiO2(Eu)/CuO nanocomposite

    Science.gov (United States)

    Michal, Robert; Dworniczek, Ewa; Caplovicova, Maria; Monfort, Olivier; Lianos, Panagiotis; Caplovic, Lubomir; Plesch, Gustav

    2016-05-01

    TiO2(Eu)/CuO nanocomposites were prepared by precipitation method. The anatase nanocrystallites with a size of 26 nm exhibited well crystallized and characteristical dipyramidal morphology and {1 0 1} and {0 0 1} faceting. Transmission electron microscopy photographs with atomic resolution showed that the Eu(III) dopants were bounded on surface of titania. In the composites, the CuO nanocrystals exhibiting a monoclinic tenorite structure with a size in the range from 2 to 5 nm were grafted to the surface of titania. The influence of copper(II) oxide led to distinct selectivity in the photocatalytic and antimicrobial properties of the investigated TiO2(Eu)/CuO nanocomposites. While the presence of CuO nanocrystals strongly increased the photocatalytic production of hydrogen by ethanol reforming, it decreased the activity in photoinduced total mineralization of phenol comparing with non-modified TiO2(Eu). In investigated TiO2(Eu)/CuO powders, the photoinduced antimicrobial activity against membranes of Enterococcus species was influenced by the selective binding of CuO to the surface of the microorganism leading to distinct selectivity in their action. The activity against Enterococcus faecalis was higher than against Enterococcus faecium.

  9. Comparison of Extensive Thermal Cycling Effects on Microstructure Development in Micro-alloyed Sn-Ag-Cu Solder Joints

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iver E.; Boesenberg, Adam; Harringa, Joel; Riegner, David; Steinmetz, Andrew; Hillman, David

    2011-09-28

    Pb-free solder alloys based on the Sn-Ag-Cu (SAC) ternary eutectic have promise for widespread adoption across assembly conditions and operating environments, but enhanced microstructural control is needed. Micro-alloying with elements such as Zn was demonstrated for promoting a preferred solidification path and joint microstructure earlier in simple (Cu/Cu) solder joints studies for different cooling rates. This beneficial behavior now has been verified in reworked ball grid array (BGA) joints, using dissimilar SAC305 (Sn-3.0Ag-0.5Cu, wt.%) solder paste. After industrial assembly, BGA components joined with Sn-3.5Ag-0.74Cu-0.21Zn solder were tested in thermal cycling (-55 C/+125 C) along with baseline SAC305 BGA joints beyond 3000 cycles with continuous failure monitoring. Weibull analysis of the results demonstrated that BGA components joined with SAC + Zn/SAC305 have less joint integrity than SAC305 joints, but their lifetime is sufficient for severe applications in consumer, defense, and avionics electronic product field environments. Failure analysis of the BGA joints revealed that cracking did not deviate from the typical top area (BGA component side) of each joint, in spite of different Ag3Sn blade content. Thus, SAC + Zn solder has not shown any advantage over SAC305 solder in these thermal cycling trials, but other characteristics of SAC + Zn solder may make it more attractive for use across the full range of harsh conditions of avionics or defense applications.

  10. Synthesis of Ag{sub 2}S–TiO{sub 2} nanocomposites and their catalytic activity towards rhodamine B photodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Sudheer Kumar; Jeevanandam, P., E-mail: jeevafcy@iitr.ac.in

    2015-11-15

    Ag{sub 2}S–TiO{sub 2} nanocomposites were prepared by a simple thermal decomposition approach. The synthesized nanocomposites were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) coupled with energy dispersive X-ray analysis (EDXA), transmission electron microscopy (TEM) and diffuse reflectance spectroscopy (DRS). XRD results indicate that the Ag{sub 2}S–TiO{sub 2} nanocomposites consist of nanocrystallites of Ag{sub 2}S and TiO{sub 2}. TEM results indicate uniform distribution of Ag{sub 2}S nanoparticles (8.8 ± 1.9 nm) in the TiO{sub 2} matrix. A blue shift of band gap of Ag{sub 2}S in the nanocomposites compared to bulk Ag{sub 2}S is observed. The Ag{sub 2}S–TiO{sub 2} nanocomposites act as good catalyst for the photodegradation of Rhodamine B in aqueous solutions in the presence of sunlight. - Highlights: • Ag{sub 2}S–TiO{sub 2} nanocomposites have been synthesized by a very simple thermal decomposition approach. • The Ag{sub 2}S–TiO{sub 2} nanocomposites show absorption in the visible region (455 nm–480 nm). • The nanocomposites act as good photocatalyst for the photodegradation of rhodamine B dye in sunlight.

  11. Microstructure and microwave properties of laser ablated Ag- and Au-doped YBa2Cu3O7-δ thin films

    International Nuclear Information System (INIS)

    Microwave transmission properties such as surface resistance, Rs and magnetic penetration depth, λ of high temperature superconductor (HTS) thin films have been found to critically depend upon the microstructure of films. In the absence of a true epitaxy, in-plane alignment determines the transport properties of HTS films. Extensive work carried out on laser ablated Ag-doped YBa2Cu3O7-δ films has shown that grain enlargement and alignment caused due to the enhanced oxygenation and surfactant action of AgO during in situ growth, significantly improves the critical current density, Jc (highest on SrTiO3: 1.4 x 107 Acm-2 at 77K) and reduces Rs (lowest on LaAlO3: 210μΩ at 77K, 10GHz). Recent results on Au-doping of YBa2Cu3O7-δ films have shown much improved film stability. Another interesting observation is that the film properties being to deteriorate above a certain thickness. This has been studied using atomic force microscopy (AFM). AFM has shown increased granularity with film thickness > 3000 A (with certain growth parameters) which has been found to increase both Rs and λ. The exact value of thickness at which film properties degrade depends upon the growth rate and other growth parameters; grain enlargement and alignment throughout the film is the key to the realization of improved microwave properties. (author)

  12. Nanoporous Ag and Pd foam: Redox induced fabrication using electrochemically deposited nanoporous Cu foam with no need to any additive

    International Nuclear Information System (INIS)

    A simple, rapid and green method for fabrication of nanoporous metal (Ag and Pd) foams using electrochemically deposited nanoporous copper foam is presented. Ideally direct electrochemical formation of Ag and Pd foam structures without any additive reagent does not lead to a desired result; however, indirect fabrication starting from electrochemically fabricated Cu foam seems promising. Highly porous copper foam is fabricated electrochemically at a copper sheet and in turn serves as a hard template and a redox inducer for the deposition of Ag or Pd. The redox induced replacement of copper foam with Ag or Pd is done via simple immersion of as-fabricated nanoporous copper foam in cation aqueous solutions of Ag or Pd. The surface morphology of the as-fabricated foam is characterized by scanning electron microscopy (SEM), EDX and X-ray diffraction. The hydrogen evolution reaction is investigated as an example to demonstrate the electrocatalytic ability of as-fabricated foams.

  13. Microstructural evolution of Cu-1at% Ti alloy aged in a hydrogen atmosphere and its relation with the electrical conductivity.

    Science.gov (United States)

    Semboshi, Satoshi; Al-Kassab, Talaat; Gemma, Ryota; Kirchheim, Reiner

    2009-04-01

    Copper alloys with titanium additions between 1 and 6at% Ti emerge currently as attractive conductive materials for electrical and electronic commercial products, since they exhibit superior mechanical and electrical properties. However, their electrical conductivity is reduced owing to the residual amount of Ti solutes in the Cu solid solution (Cu(ss)) phase. Since Cu shows only poor reactivity with hydrogen (H), while Ti exhibits high affinity to it, we were inspired by the idea that hydrogenation of Cu-Ti alloys would influence their microstructure, resulting in a significant change of their properties. In this contribution, the influence of aging under a deuterium (D(2)) atmosphere of Cu-1at% Ti alloys on their microstructure is investigated to explore the effects on the electrical conductivity. The specimens were investigated by means of transmission electron microscopy (TEM), field ion microscopy (FIM), computer-aided field ion image tomography (cFIIT), and atom probe tomography (APT). At an early aging stage at 623K in a D(2) atmosphere of 0.08MPa, ellipsoidal alpha-Cu(4)Ti precipitates are formed in the alloy, and during subsequent aging, delta-TiD(2) is competitively nucleated instead of growth of alpha-Cu(4)Ti particles. The co-precipitation of alpha-Cu(4)Ti and delta-TiD(2) efficiently reduces the Ti concentration of Cu(ss) matrix, particularly in the later aging stages in comparison to the aging in vacuum conditions. The electrical conductivity of the alloy aged in the D(2) atmosphere increases steeply up to 48% International Annealed Copper Standard (IACS) after 1030h, while it saturates to approximately 20% IACS in the alloy aged in vacuum. The outstanding increase of electrical conductivity during aging in D(2) atmosphere can be basically explained by the reduction of Ti solute concentration in Cu(ss) matrix. PMID:19243888

  14. Instability of TiC and TiAl3 compounds in Al-10Mg and Al-5Cu alloys by addition of Al-Ti-C master alloy

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The performance of Al-Ti-C master alloy in refining Al-10Mg and A1-5Cu alloys was studied by using electron probe micro-analyzer (EPMA) and X-ray diffractometer (XRD) analysis.The results indicate that there are obvious fading phenomena in both Al-10Mg and Al-5Cu alloys with the addition of Al-5Ti-0.4C refiner which contains TiC and TiAl3 compounds.Mg element has no influence on the stability of TiC and TiAl3, while TiC particles in Al-10Mg alloy react with Al to form Al4C3 particles, resulting in the refinement fading.However, TiC particles are relatively stable in Al-5Cu alloy, while TiAl3 phase reacts with Al2Cu to produce a new phase Ti(Al, Cu)2, which is responsible for the refinement fading in Al-5Cu alloy.These indicate that the refinement fading will not occur only when both the TiC particles and TiAl3 compound of Al-Ti-C refiner are stable in Al alloys.

  15. Surface modification of additive manufactured Ti6Al4V alloy with Ag nanoparticles: wettability and surface morphology study

    Science.gov (United States)

    Chudinova, E.; Surmeneva, M.; Koptioug, A.; Sharonova, A.; Loza, K.; Surmenev, R.

    2016-02-01

    In this work, the use of electrophoretic deposition to modify the surface of Ti6Al4V alloy fabricated via additive manufacturing technology is reported. Poly(vinylpyrrolidone) (PVP)-stabilized silver nanoparticles (AgNPs) had a spherical shape with a diameter of the metallic core of 100±20 nm and ζ -potential -15 mV. The AgNPs- coated Ti6Al4V alloy was studied in respect with its chemical composition and surface morphology, water contact angle, hysteresis, and surface free energy. The results of SEM microphotography analysis showed that the AgNPs were homogeneously distributed over the surface. Hysteresis and water contact angle measurements revealed the effect of the deposited AgNPs layer, namely an increased water contact angle and decreased contact angle hysteresis. However, the average water contact angle was 125° for PVP-stabilized-AgNPs-coated surface, whereas ethylene glycol gave the average contact angle of 17°. A higher surface energy is observed for AgNPs-coated Ti6Al4V surface (70.17 mN/m) compared with the uncoated surface (49.07 mN/m).

  16. Aqueous transition-metal cations as impurities in a wide gap oxide: the Cu(2+)/Cu(+) and Ag(2+)/Ag(+) redox couples revisited.

    Science.gov (United States)

    Liu, Xiandong; Cheng, Jun; Sprik, Michiel

    2015-01-22

    The interactions of the d electrons of transition-metal aqua ions with the solvent are usually divided in short-range electronic interactions with ligand water molecules and long-range electrostatic interactions with molecules beyond the first coordination shell. This is the rationale behind the cluster continuum and QM/MM methods developed for the computation of the redox potentials. In the density functional theory based molecular dynamics (DFTMD) method, the electronic states of the complex are also allowed to mix with the extended band states of the solvent. Returning to the Cu(+) and Ag(+) oxidation reaction, which has been the subject of DFTMD simulation before, we show that coupling to the valence band states of water is greatly enhanced by the band gap error in the density functional approximation commonly used in DFTMD (the generalized gradient approximation). This effect is analyzed by viewing the solvent as a wide gap oxide and the redox active ions as electronic defects. The errors can be reduced significantly by application of hybrid functionals containing a fraction of Hartree-Fock exchange. These calculations make use of recent progress in DFTMD technology, enabling us to include sp core polarization and Hartree-Fock exchange in condensed-phase model systems. PMID:25386900

  17. Effect of Cooling Rate on the Longitudinal Modulus of Cu3Sn Phase of Ag-Sn-Cu Amalgam Alloy (Part II)

    OpenAIRE

    R. H. Rusli

    2015-01-01

    Effects of cooling rate (at the time of solidification on the elastic constants of Cu3Sn phase of Ag-Sn-Cu dental amalgam alloy were studied. In this study, three types of alloys were made, with the composition Cu-38-37 wt% Sn by means of casting, where each alloy was subjected to different cooling rate, such as cooling on the air (AC), air blown (AB), and quenched in the water (WQ). X-ray diffraction, metallography, and Scanning Electron Microscopy with Energy Dispersive Spectroscopy studies...

  18. Synthesis and characterization of high photocatalytic activity and stable Ag3PO4/TiO2 fibers for photocatalytic degradation of black liquor

    Science.gov (United States)

    Cai, Li; Long, Qiyi; Yin, Chao

    2014-11-01

    The TiO2 fiber was prepared by using cotton fiber as a template, and then Ag3PO4/TiO2 fibers were synthesized via in situ Ag3PO4 particles onto the surface of TiO2 fiber. Their structure and physical properties were characterized by means of scanning electron microscopy (SEM), specific surface analyzer, X-ray diffraction (XRD), UV-vis absorption spectra and photoluminescence spectra (PL). SEM analysis indicated that the well-defined surface morphology of natural cotton fiber was mostly preserved in TiO2 and Ag3PO4/TiO2 fibers. Compared with TiO2 fiber, the absorbance wavelengths of Ag3PO4/TiO2 fibers were apparently red shifted and the PL intensities revealed a significant decrease. By using the photocatalytic degradation of black liquor as a model reaction, the visible light and ultraviolet light catalytic efficiencies of TiO2, Ag3PO4 and Ag3PO4/TiO2 fibers were evaluated. The reaction results showed that Ag3PO4/TiO2 fibers had stronger photocatalytic activity and excellent chemical stability in repeated and long-term applications. Therefore, the prepared Ag3PO4/TiO2 fibers could act as an efficient catalyst for the photocatalytic degradation of black liquor, which suggested their promising applications. It was proposed that the •OH radicals played the leading role in the photocatalytic degradation of the black liquor by Ag3PO4/TiO2 fibers system.

  19. Mechanism and experimental study on the photocatalytic performance of Ag/AgCl @ chiral TiO{sub 2} nanofibers photocatalyst: The impact of wastewater components

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dawei [Key Laboratory of Integrated Regulation and Resource Development of Shallow Lakes, Ministry of Education, College of Environment, Hohai University. Xi Kang Road #1, Nanjing 210098 (China); Li, Yi, E-mail: envly@hhu.edu.cn [Key Laboratory of Integrated Regulation and Resource Development of Shallow Lakes, Ministry of Education, College of Environment, Hohai University. Xi Kang Road #1, Nanjing 210098 (China); Li Puma, Gianluca [Environmental Nanocatalysis & Photoreaction Engineering, Department of Chemical Engineering, Loughborough University, Loughborough LE11 3TU (United Kingdom); Wang, Chao; Wang, Peifang; Zhang, Wenlong; Wang, Qing [Key Laboratory of Integrated Regulation and Resource Development of Shallow Lakes, Ministry of Education, College of Environment, Hohai University. Xi Kang Road #1, Nanjing 210098 (China)

    2015-03-21

    Highlights: • The effect of wastewater matrix on Ag/AgCl based nanomaterials was investigated. • DOM acted as a reactive oxygen species scavenger. • Cl{sup −} could accelerate the transformation from Ag to AgCl. • A relative rate technique was used to quantify these components impacts. - Abstract: The effect of the water matrix components of a secondary effluent of a urban wastewater treatment plant on the photocatalytic activity of Ag/AgCl @ chiral TiO{sub 2} nanofibers and the undergoing reaction mechanisms were investigated. These effects were evaluated through the water components-induced changes on the net rate of hydroxyl radical (·OH) generation and modeled using a relative rate technique. Dissolved organic matter DOM (k = −2.8 × 10{sup 8} M{sup −1} s{sup −1}) scavenged reactive oxygen species, Cl{sup −} (k = −5.3 × 10{sup 8} M{sup −1} s{sup −1}) accelerated the transformation from Ag to AgCl (which is not photocatalytically active under visible-light irradiation), while Ca{sup 2+} at concentrations higher than 50 mM (k = −1.3 × 10{sup 9} M{sup −1} s{sup −1}) induced aggregation of Ag/AgCl and thus all of them revealed inhibitory effects. In contrast, NO{sub 3}{sup −} (k = 6.9 × 10{sup 8} M{sup −1} s{sup −1}) and CO{sub 3}{sup 2−} (k = 3.7 × 10{sup 8} M{sup −1} s{sup −1}) improved the photocatalytic activity of Ag/AgCl slightly by improving the rate of HO· generation. Other ubiquitous secondary effluent components including SO{sub 4}{sup 2−} (k = 3.9 × 10{sup 5} M{sup −1} s{sup −1}), NH{sub 3}{sup +} (k = 3.5 × 10{sup 5} M{sup −1} s{sup −1}) and Na{sup +} (k = 2.6 × 10{sup 4} M{sup −1} s{sup −1}) had negligible effects. 90% of 17-α-ethynylestradiol (EE2) spiked in the secondary effluent was removed within 12 min, while the structure and size of Ag/AgCl @ chiral TiO{sub 2} nanofibers remained stable. This work may be helpful not only to uncover the photocatalytic mechanism of Ag/AgCl based

  20. Environmentally friendly electroless plating for Ag/TiO2-coated core-shell magnetic particles using ultrasonic treatment.

    Science.gov (United States)

    Kim, Soo-Dong; Choe, Won-Gyun; Jeong, Jong-Ryul

    2013-11-01

    In this work, high-reflectance brilliant white color magnetic microspheres comprising a Fe/TiO2/Ag core-shell structure with a continuous, uniform compact silver layer were successfully fabricated by TiO2-assisted electroless plating in a simple and eco-friendly method. The coating procedure for TiO2 and Ag involved a sol-gel reaction and electroless plating with ultrasound treatment. The electroless plating step was carried out in an eco-friendly manner in a single process without environmentally toxic additives. The TiO2 layer was used as a modification layer between the Fe microspheres and the silver layer to improve adhesion. A continuous and compact silver layer could be formed with a high degree of morphological control by introducing ultrasonication and adjusting the ammonium hydroxide concentration. PMID:23611665

  1. The Cu2FeTi3S8 and Cu2FeZr3S8 compounds: Crystal structure and electroanalytical application

    International Nuclear Information System (INIS)

    The Cu2FeTi3S8 and Cu2FeZr3S8 compounds were produced by solid-state synthesis. The crystal structure of the quaternary phases was investigated by X-ray powder method. The compounds are described in the thiospinel structure (space group Fd3-bar m) with the unit cell parameters a = 1.00099(1) nm (Cu2FeTi3S8) and a = 1.03837(2) nm (Cu2FeZr3S8). The atomic parameters were calculated in the isotropic approximation (RI = 0.0496 and RI = 0.0422 for Cu2FeTi3S8 and Cu2FeZr3S8, respectively). Iron(III)-selective electrodes were prepared using the chalcogenide compounds Cu2FeTi3S8 and Cu2FeZr3S8. The electrode function slopes are 52.7 mV/pC for Cu2FeTi3S8 and 66.2 mV/pC for Cu2FeZr3S8, the detection limits are 1 x 10-5 M and 2 x 10-5 M respectively. The prepared electrochemical sensors are not sensitive to Cd2+, Zn2+, Mn2+, Ni2+, Co2+, Mg2+, Cr3+, and Fe2+ ions, and were tested in the potentiometric titration of Fe(III) with EDTA solution.

  2. Microstructure and corrosion resistance of Ti-Zr-Cu-Pd-Sn glassy and nanocrystalline alloys

    International Nuclear Information System (INIS)

    The microstructure and corrosion behavior of the Ti47.5Zr15Cu30Pd7.5Sn5 as-spun ribbons and as-cast rod have been investigated using HREM and potentiodynamic polarization study in simulated body fluids. The results of HREM reveal that, with decreasing cooling rate, the size and volume of nano-particles dispersed in glassy matrix increase for the Ti47.5Zr15Cu30Pd7.5Sn5 as-prepared samples. The as-spun ribbons with small size nano-particle show high corrosion resistance in PBS(-) and Hanks' solution, may be due to the formation of CuZr phase, resulting in the enrichment of Ti and Pd in the glassy matrix, which is helpful to form protective passive film. Comparatively, poor corrosion resistance is observed for the as-cast rod sample with larger nano-particles in both solutions. (author)

  3. Martensitic transformation of Ti50Ni30Cu20 alloy prepared by powder metallurgy

    Energy Technology Data Exchange (ETDEWEB)

    Valeanu, M., E-mail: valeanu@infim.ro [National Institute of Materials Physics, 077125 Bucharest (Romania); Lucaci, M. [National Institute for Electrical Engineering ICPE-CA, 030138 Bucharest (Romania); Crisan, A.D.; Sofronie, M. [National Institute of Materials Physics, 077125 Bucharest (Romania); Leonat, L. [National Institute for Electrical Engineering ICPE-CA, 030138 Bucharest (Romania); Kuncser, V. [National Institute of Materials Physics, 077125 Bucharest (Romania)

    2011-03-31

    Research highlights: > Martensitic transformation sequence in Ti50Ni30Cu20 prepared high - energy milling. > Two transformations (B2-B19, B2-B19') are evidenced after 10 hours of milling. > B2-B19 transformation is not more observed after 20 hours of milling. > A longer milling process promotes the formation of the secondary Ti{sub 2}(NiCu) phase. - Abstract: Phase transformation behavior of Ti50Ni30Cu20 shape memory alloys prepared by powder metallurgy is analyzed with respect to the duration of mechanical alloying. The processed blends were studied by differential scanning calorimetry and room temperature X-ray diffraction. The martensitic transformations evidenced by thermal scans are discussed in correlation with the relative phase content obtained from the refinement of the X-ray diffraction patterns.

  4. Nanopaper based on Ag/TiO{sub 2} nanobelts heterostructure for continuous-flow photocatalytic treatment of liquid and gas phase pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Weijia; Du, Guojun; Hu, Peiguang [State Key Laboratory of Crystal Materials, Center of Bio and Micro/Nano Functional Materials, Shandong University, 27 Shandanan Road, Jinan 250100 (China); Yin, Yongquan [The School of Environmental Science and Engineering, Shandong University, 27 Shandanan Road, Jinan 250100 (China); Li, Jianhua [State Key Laboratory of Crystal Materials, Center of Bio and Micro/Nano Functional Materials, Shandong University, 27 Shandanan Road, Jinan 250100 (China); Yu, Jiahong [The School of Environmental Science and Engineering, Shandong University, 27 Shandanan Road, Jinan 250100 (China); Wang, Guancong [State Key Laboratory of Crystal Materials, Center of Bio and Micro/Nano Functional Materials, Shandong University, 27 Shandanan Road, Jinan 250100 (China); Wang, Jinxia [School of Light Chemistry and Environment Engineering, Shandong Polytechnic University, Daxue Road, Western University Science Park, Jinan 250353 (China); Liu, Hong, E-mail: hongliu@sdu.edu.cn [State Key Laboratory of Crystal Materials, Center of Bio and Micro/Nano Functional Materials, Shandong University, 27 Shandanan Road, Jinan 250100 (China); Wang, Jiyang, E-mail: jywang@icm.sdu.edu.cn [State Key Laboratory of Crystal Materials, Center of Bio and Micro/Nano Functional Materials, Shandong University, 27 Shandanan Road, Jinan 250100 (China); Zhang, Hua [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer The photocatalytic activity of TiO{sub 2} nanobelts is evidently enhanced by the heterostructures between Ag nanoparticles and TiO{sub 2} nanobelts. Black-Right-Pointing-Pointer The nanopapers based on Ag/TiO{sub 2} nanobelt heterostructures are fabricated via a modified paper-making process. Black-Right-Pointing-Pointer A continuous flow photocatalytic reactor is designed. Black-Right-Pointing-Pointer The TiO{sub 2} nanopapers in the microreactor show an excellent continuous photocatalytic performance for liquid and gas phase pollutants. Black-Right-Pointing-Pointer The Ag/TiO{sub 2} nanobelts nanopaper shows a good antibacterial effect. - Abstract: The Ag/TiO{sub 2} nanobelt heterostructures were prepared by the acid-assisted hydrothermal method followed by an in situ photo-reduction process. The photocatalytic activity of TiO{sub 2} nanobelts was evidently enhanced by the heterostructures between Ag nanoparticles and TiO{sub 2} nanobelts. The nanopapers based on Ag/TiO{sub 2} nanobelt heterostructures were fabricated via a modified paper-making process. A novel continuous photocatalytic reactor was designed, and MO removal rate of Ag/C-TiO{sub 2} nanopaper was achieved to 100% in 40 min for single layer and only in 6 min for three layers. The self-supported TiO{sub 2} nanopapers with porous structures also showed an excellent continuous photocatalytic performance for toluene gas under UV light irradiation, and the corresponding degradation rate was 69.5% in 184 min. Moreover, the Ag/TiO{sub 2} nanobelts nanopaper showed a good antibacterial effect. The multifunctional TiO{sub 2} nanopapers modified by the heterostuctures could have potential applications in the environmental and biomaterial fields.

  5. Nanopaper based on Ag/TiO2 nanobelts heterostructure for continuous-flow photocatalytic treatment of liquid and gas phase pollutants

    International Nuclear Information System (INIS)

    Highlights: ► The photocatalytic activity of TiO2 nanobelts is evidently enhanced by the heterostructures between Ag nanoparticles and TiO2 nanobelts. ► The nanopapers based on Ag/TiO2 nanobelt heterostructures are fabricated via a modified paper-making process. ► A continuous flow photocatalytic reactor is designed. ► The TiO2 nanopapers in the microreactor show an excellent continuous photocatalytic performance for liquid and gas phase pollutants. ► The Ag/TiO2 nanobelts nanopaper shows a good antibacterial effect. - Abstract: The Ag/TiO2 nanobelt heterostructures were prepared by the acid-assisted hydrothermal method followed by an in situ photo-reduction process. The photocatalytic activity of TiO2 nanobelts was evidently enhanced by the heterostructures between Ag nanoparticles and TiO2 nanobelts. The nanopapers based on Ag/TiO2 nanobelt heterostructures were fabricated via a modified paper-making process. A novel continuous photocatalytic reactor was designed, and MO removal rate of Ag/C–TiO2 nanopaper was achieved to 100% in 40 min for single layer and only in 6 min for three layers. The self-supported TiO2 nanopapers with porous structures also showed an excellent continuous photocatalytic performance for toluene gas under UV light irradiation, and the corresponding degradation rate was 69.5% in 184 min. Moreover, the Ag/TiO2 nanobelts nanopaper showed a good antibacterial effect. The multifunctional TiO2 nanopapers modified by the heterostuctures could have potential applications in the environmental and biomaterial fields.

  6. Sn-Ag-Cu to Cu joint current aging test and evolution of resistance and microstructure

    Science.gov (United States)

    Xu, Di Erick; Chow, Jasper; Mayer, Michael; Jung, Jae Pil; Yoon, Jong Hyun

    2015-11-01

    SAC 305 solder bump with 800 μm diameter were produced and soldered to a custom substrate with Cu lines as leads that allow for resistance measurement during current aging. The measured joint resistance values (leads plus solder bump) before aging are 7.7 ± 1.8 mΩ and 11.8 ± 2.8 mΩ at room temperature and 160°C, respectively. In general, the resistance of the solder joint increases instantly by about 1 mΩ, when subjected to a 2.2 A aging current at 160°C. The increase is gradual in the following hours of aging and more drastic as it approaches the final failure. Four stages are identified in the resistance signal curve and compared with observations from cross sections. The stages are IMC growth, crack formation and propagation, intermittent crack healing-forming, and final failure resulting in an open connection at the cathode. Recently a periodical drop and rise behavior was reported for the resistance signal. This behavior is reproduced and attributed to the intermittent crack healing-forming stage. The healing events observed are faster than the sampling time. Possibly, as current is concentrated when bypassing interfacial cracks, local melting occurs partially filling cracks before resolidifying. [Figure not available: see fulltext.

  7. Characterization of a NiTiCu shape memory alloy produced by powder technology

    Directory of Open Access Journals (Sweden)

    J. Van Humbeeck

    2006-04-01

    Full Text Available Purpose: The main aim of presented work was to find a sintering conditions (temperature and time for manufacturing of a Ni(1-XTi50CuX alloy (where X = 2; 3; 5; 10; 15; 20 and 25at%. by powder technology.Design/methodology/approach: Various conditions of sintering considering temperature and time were applied to compacted powders. Sintering temperature varied from 850°C to 1100°C and sintering time was chosen from a range of 5 to 50 hours, respectively. Microstructure, structure, chemical composition and thermal behavior of sintered blends were studied by scanning electron microscopy (SEM, differential scanning calorimetry (DSC and X-ray diffraction.Findings: Homogenous alloys, containing lower addition of copper (less than 10 at%, were sintered at 940°C for 7 hours. For higher copper content (10-25at% lower sintering temperature 8500C but longer sintering time was preferred (20 hours. The quality of the alloy was characterized by porosity and density. In sintered blends non-transformable phases Ti2(Ni,Cu and (Ni,Cu3Ti, which posses the crystal structure of Ti2Ni and Cu3Ti respectively, were found. Despite the fact that same sintering conditions lead to an increase of inhomogeneity all sintered alloys reveal the presence of the reversible martensitic transformation.Practical implications: Obtained results allowed to optimize sintering condition for NiTiCu shape memory alloy manufacturing.Originality/value: A NiTiCu shape memory alloy, with various content of copper, was successfully produced by powder metallurgy.

  8. Thermodynamic and electrical properties of CuCrTiS4

    International Nuclear Information System (INIS)

    Highlights: • We study thermodynamic and electrical properties of spinel CuCrTiS4. • Electrical resistivity shows insulating temperature dependence. • Thermal conductivity has the contribution from the localized vibration hopping mode. • Thermopower can be reproduced by the Matoba’s model in the wide temperature range. • CuCrTiS4 has a dimensionless figure of merit of 0.01 at 300 K. - Abstract: We studied the electrical resistivity, thermal conductivity, and thermopower of thiospinel CuCrTiS4. Temperature (T) dependence of the electrical resistivity (ρ) is insulating in the whole temperature range we measured, 5CuCrTiS4, with T increasing, monotonically-increasing behaviour as seen in the amorphous compounds is observed in 150KCuCrTiS4 is negative. The absolute value of S(T) has a broad peak caused by phonon drag at around 30 K, and the linear temperature dependence in 80KCuCrTiS4 is ∼0.01 at around 300 K

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